diff --git a/docs/backend/FRONTEND_COZSWEET_BEHAVIOR_ANALYTICS.md b/docs/backend/FRONTEND_COZSWEET_BEHAVIOR_ANALYTICS.md
new file mode 100644
index 00000000..c3bd35aa
--- /dev/null
+++ b/docs/backend/FRONTEND_COZSWEET_BEHAVIOR_ANALYTICS.md
@@ -0,0 +1,267 @@
+# Cozsweet 全站行为埋点前端接入
+
+> 发布状态（2026-07-14）：自动页面/按钮采集 SDK 已部署 `pro` 预发，生产仍是旧版支付专项 SDK。前端应先接 `pro` 完成联调；生产自动采集要等 unified 下一次生产镜像发布后再启用。
+
+## 1. 目标
+
+前端接入一次后，自动统计：
+
+- 用户访问了哪个页面。
+- Next.js 站内路由切换。
+- 所有原生按钮、链接和带 `role="button"` 的控件点击。
+- 带 `data-analytics-key` 的自定义可点击组件。
+
+支付漏斗另外上报明确业务事件，统计付费墙原因、套餐曝光、套餐点击、创建订单、打开支付页和最终支付结果。
+
+## 2. 环境地址
+
+| 环境 | SDK | 事件接口 |
+| --- | --- | --- |
+| pro 预发 | `https://proapi.banlv-ai.com/js/cozsweet-payment-analytics.js` | `https://proapi.banlv-ai.com/api/behavior/events` |
+| production 生产 | `https://api.banlv-ai.com/js/cozsweet-payment-analytics.js` | `https://api.banlv-ai.com/api/behavior/events` |
+
+## 3. Next.js 根布局接入
+
+只在根布局加载一次。预发必须先指定预发事件地址，否则 SDK 默认发送到生产。
+
+```tsx
+import Script from 'next/script'
+
+export function BehaviorAnalyticsScripts() {
+  const isPro = process.env.NEXT_PUBLIC_APP_ENV === 'pro'
+  const apiBase = isPro
+    ? 'https://proapi.banlv-ai.com'
+    : 'https://api.banlv-ai.com'
+
+  return (
+    <>
+      <Script id="cozsweet-analytics-config" strategy="beforeInteractive">
+        {`window.COZSWEET_ANALYTICS_ENDPOINT=${JSON.stringify(
+          `${apiBase}/api/behavior/events`,
+        )}`}
+      </Script>
+      <Script
+        src={`${apiBase}/js/cozsweet-payment-analytics.js`}
+        strategy="afterInteractive"
+      />
+    </>
+  )
+}
+```
+
+SDK 会自动生成并持久化：
+
+- `anonymousId`：未登录用户标识。
+- `sessionId`：30 分钟会话标识。
+- `pagePath/pageTitle/referrer`。
+- `siteHost/pageUrl/UTM`。
+
+登录成功或恢复会话后设置 Token，让事件同时绑定 `userId`：
+
+```ts
+window.CozsweetPaymentAnalytics?.setToken(accessToken)
+```
+
+## 4. 所有按钮点击
+
+以下元素会自动上报 `eventType=element_click`，前端不需要在每个 `onClick` 里手工请求接口：
+
+- `button`
+- `a[href]`
+- `[role="button"]`
+- `[role="link"]`
+- `input[type="button|submit|reset"]`
+- `[data-analytics-key]`
+
+重要按钮必须提供稳定且不随语言变化的 `data-analytics-key`：
+
+```tsx
+<button data-analytics-key="chat.send_message">Send</button>
+
+<button data-analytics-key="recharge.open" data-analytics-label="Open recharge">
+  Recharge
+</button>
+
+<div
+  role="button"
+  data-analytics-key="private_album.unlock"
+  data-analytics-label="Unlock private album"
+  onClick={unlockAlbum}
+/>
+```
+
+纯 `div onClick` 如果没有 `role="button"`，必须添加 `data-analytics-key`，否则浏览器无法可靠识别它是按钮。
+
+不需要统计的区域：
+
+```tsx
+<div data-analytics-ignore>
+  {/* 此节点及其子节点不自动记录点击 */}
+</div>
+```
+
+程序触发、没有真实 DOM 点击时可以手工记录：
+
+```ts
+window.CozsweetPaymentAnalytics?.elementClick(
+  'chat.retry_generation',
+  'Retry generation',
+  { messageId },
+)
+```
+
+不要把聊天正文、邮箱、手机号、Token 或支付参数放进 `data-analytics-key`、标签或 metadata。
+
+## 5. 支付漏斗必须手工上报
+
+通用按钮点击只能知道“点了某个按钮”，不能知道套餐价格、订单 ID 和进入充值页的原因。以下事件必须在支付业务代码对应步骤调用。
+
+```ts
+const analytics = window.CozsweetPaymentAnalytics
+
+analytics?.paywallShown('daily_chat_limit', {
+  entryPoint: 'chat_input',
+  isVip: false,
+})
+
+analytics?.rechargeModalOpen('chat_input', 'daily_chat_limit')
+
+plans.forEach((plan, index) => {
+  analytics?.planImpression(plan, index + 1)
+})
+
+analytics?.planClick(plan, {
+  entryPoint: 'paywall_modal',
+  triggerReason: 'daily_chat_limit',
+})
+
+analytics?.createOrderStart(plan, payChannel)
+
+try {
+  const response = await createOrder({
+    planId: plan.planId,
+    payChannel,
+    autoRenew,
+  })
+  const data = response.data
+  const orderId = data.orderId
+  const checkoutUrl = analytics?.extractCheckoutUrl(data)
+
+  analytics?.createOrderSuccess(plan, orderId, payChannel)
+  if (checkoutUrl) {
+    analytics?.checkoutOpened(orderId, plan, payChannel, checkoutUrl)
+    window.location.href = checkoutUrl
+  } else {
+    analytics?.checkoutFailed(
+      orderId,
+      plan,
+      'missing_checkout_url',
+      payChannel,
+    )
+  }
+} catch (error) {
+  analytics?.createOrderFailed(
+    plan,
+    error instanceof Error ? error.message : 'create_order_error',
+    payChannel,
+  )
+}
+```
+
+轮询订单状态：
+
+```ts
+analytics?.statusPollStart(orderId, plan)
+
+analytics?.statusPollUpdate(orderId, data.status, plan, {
+  expiresAt: data.expiresAt,
+  expiresInSeconds: data.expiresInSeconds,
+})
+
+// 前端主动放弃轮询且订单仍未进入终态时调用
+analytics?.statusPollTimeout(orderId, plan)
+```
+
+## 6. 固定事件名
+
+| 步骤 | 事件名 | 必要 metadata |
+| --- | --- | --- |
+| 触发付费墙 | `paywall_shown` | `triggerReason`, `entryPoint` |
+| 打开充值页 | `recharge_modal_open` | `triggerReason`, `entryPoint` |
+| 套餐曝光 | `payment_plan_impression` | `planId`, `amountCents`, `currency`, `position` |
+| 点击套餐 | `payment_plan_click` | `planId`, `amountCents`, `currency` |
+| 开始建单 | `payment_create_order_start` | `planId`, `payChannel` |
+| 建单成功 | `payment_create_order_success` | `planId`, `orderId`, `payChannel` |
+| 建单失败 | `payment_create_order_failed` | `planId`, `reason`, `payChannel` |
+| 打开支付页 | `payment_checkout_opened` | `planId`, `orderId`, `payChannel` |
+| 支付页缺失/打开失败 | `payment_checkout_failed` | `orderId`, `reason` |
+| 支付状态 | `payment_status_paid/failed/expired` | `orderId`, `status` |
+| 轮询超时 | `payment_status_poll_timeout` | `orderId` |
+
+`triggerReason` 使用固定值：
+
+- `daily_chat_limit`
+- `private_topic_limit`
+- `insufficient_credits`
+- `sidebar_recharge`
+- `vip_cta`
+- `ad_landing`
+- `manual_recharge`
+- `unknown`
+
+不要继续使用已经废弃的 `weekly_chat_limit` 作为新事件原因；当前免费聊天口径是每日额度。
+
+## 7. 请求格式
+
+SDK 最终批量发送：
+
+```http
+POST /api/behavior/events
+Content-Type: application/json
+Authorization: Bearer <TOKEN>  // 有登录 Token 时携带
+```
+
+```json
+{
+  "events": [
+    {
+      "eventType": "element_click",
+      "eventName": "element_click",
+      "anonymousId": "browser-uuid",
+      "sessionId": "session-uuid",
+      "pagePath": "/chat",
+      "pageTitle": "Chat",
+      "elementKey": "recharge.open",
+      "elementText": "Recharge",
+      "elementTag": "button",
+      "metadata": {
+        "siteHost": "cozsweet.com",
+        "pageUrl": "https://cozsweet.com/chat"
+      }
+    }
+  ]
+}
+```
+
+成功响应：
+
+```json
+{"ok": true, "inserted": 1}
+```
+
+埋点失败不能阻塞聊天、解锁或支付流程。SDK 已吞掉网络异常，业务代码不要 `await` 埋点后再继续支付。
+
+## 8. 联调验收
+
+1. 打开浏览器 Network，筛选 `behavior/events`。
+2. 首次打开页面应看到 `page_view`。
+3. Next.js 路由切换后应再次看到新 `pagePath` 的 `page_view`。
+4. 点击任意按钮应看到 `element_click` 和稳定 `elementKey`。
+5. 从付费墙点击一个套餐，依次检查专用支付事件及 `planId`。
+6. 建单成功后必须看到同一 `orderId` 出现在建单、支付页和状态事件中。
+7. 接口响应必须为 `ok=true` 且 `inserted>0`。
+8. Manager 选择同一日期范围，确认数据出现；统计不是实时推送时，刷新页面即可。
+
+## 9. 当前线上为 0 的原因
+
+截至 2026-07-14，线上 `cozsweet.com` 页面及加载的前端 JS 中没有找到本 SDK，也没有找到支付漏斗事件代码。数据库近期大部分 `element_click/page_view` 来自 Manager 后台自己的追踪，而不是 Cozsweet 用户端。后端只能自动记录建单开始/成功/失败，无法替前端知道付费墙是否展示、套餐是否曝光、用户点击了哪个套餐、支付页是否真正打开，因此这些步骤显示 0 是符合当前数据事实的。
diff --git a/env-example/.env.production.example b/env-example/.env.production.example
index 01b9526a..2217024d 100644
--- a/env-example/.env.production.example
+++ b/env-example/.env.production.example
@@ -6,10 +6,10 @@ NEXTAUTH_URL=https://cozsweet.com
 NEXTAUTH_URL_INTERNAL=http://localhost:3000
 
 # 后端 API 基础 URL（生产环境）
-NEXT_PUBLIC_API_BASE_URL=https://api.cozsweet.com
+NEXT_PUBLIC_API_BASE_URL=https://api.banlv-ai.com
 
 # WebSocket URL（生产环境）
-NEXT_PUBLIC_WS_BASE_URL=wss://api.cozsweet.com/ws
+NEXT_PUBLIC_WS_BASE_URL=wss://api.banlv-ai.com/ws
 
 # Stripe 支付（publishable key 可暴露在浏览器端）
 NEXT_PUBLIC_STRIPE_PUBLISHABLE_KEY=pk_live_51Te8ybEJDtUGxQHouKlEMfMuCZWifzlhBIReeKvANOtyCXS4zL0SMTWJXiFHPKz7azpF6OnIKXUPFSLs82fevVjr00w1bw5mvl
diff --git a/src/app/_components/__tests__/tailwind-components.test.tsx b/src/app/_components/__tests__/tailwind-components.test.tsx
index f8a38291..a217d314 100644
--- a/src/app/_components/__tests__/tailwind-components.test.tsx
+++ b/src/app/_components/__tests__/tailwind-components.test.tsx
@@ -14,7 +14,12 @@ describe("shared Tailwind components", () => {
       <BackButton onClick={() => undefined} variant="ghost" />,
     );
     const darkHtml = renderToStaticMarkup(
-      <BackButton href="/splash" variant="dark" ariaLabel="Back to home" />,
+      <BackButton
+        href="/splash"
+        variant="dark"
+        ariaLabel="Back to home"
+        analyticsKey="chat.back_to_home"
+      />,
     );
 
     expect(linkHtml).toContain('href="/chat"');
@@ -27,6 +32,7 @@ describe("shared Tailwind components", () => {
     expect(actionHtml).toContain("hover:opacity-70");
     expect(darkHtml).toContain('href="/splash"');
     expect(darkHtml).toContain('aria-label="Back to home"');
+    expect(darkHtml).toContain('data-analytics-key="chat.back_to_home"');
     expect(darkHtml).toContain("bg-[rgba(13,11,20,0.7)]");
     expect(darkHtml).toContain("text-white");
   });
diff --git a/src/app/_components/back-button.tsx b/src/app/_components/back-button.tsx
index 7338075f..613c0567 100644
--- a/src/app/_components/back-button.tsx
+++ b/src/app/_components/back-button.tsx
@@ -6,6 +6,7 @@ import Link, { type LinkProps } from "next/link";
 interface BackButtonBaseProps {
   className?: string;
   ariaLabel?: string;
+  analyticsKey?: string;
   iconSize?: number;
   variant?: "floating" | "soft" | "ghost" | "dark";
 }
@@ -41,6 +42,7 @@ export function BackButton({
   onClick,
   className,
   ariaLabel = "Back",
+  analyticsKey,
   iconSize = 24,
   variant = "floating",
 }: BackButtonProps) {
@@ -57,7 +59,13 @@ export function BackButton({
 
   if (href) {
     return (
-      <Link href={href} className={buttonClassName} aria-label={ariaLabel}>
+      <Link
+        href={href}
+        className={buttonClassName}
+        aria-label={ariaLabel}
+        data-analytics-key={analyticsKey}
+        data-analytics-label={ariaLabel}
+      >
         {icon}
       </Link>
     );
@@ -69,6 +77,8 @@ export function BackButton({
       className={buttonClassName}
       onClick={onClick}
       aria-label={ariaLabel}
+      data-analytics-key={analyticsKey}
+      data-analytics-label={ariaLabel}
     >
       {icon}
     </button>
diff --git a/src/app/_components/core/__tests__/tailwind-components.test.tsx b/src/app/_components/core/__tests__/tailwind-components.test.tsx
index 7348710b..749e4049 100644
--- a/src/app/_components/core/__tests__/tailwind-components.test.tsx
+++ b/src/app/_components/core/__tests__/tailwind-components.test.tsx
@@ -101,5 +101,9 @@ describe("core Tailwind components", () => {
     expect(privateRoomHtml).toMatch(
       /<button[^>]*aria-current="page"[^>]*>.*?<span>Elio Private room<\/span>/,
     );
+    expect(chatHtml).toContain('data-analytics-key="navigation.chat"');
+    expect(privateRoomHtml).toContain(
+      'data-analytics-key="navigation.private_room"',
+    );
   });
 });
diff --git a/src/app/_components/core/app-bottom-nav.tsx b/src/app/_components/core/app-bottom-nav.tsx
index c9b31fac..cee62e8c 100644
--- a/src/app/_components/core/app-bottom-nav.tsx
+++ b/src/app/_components/core/app-bottom-nav.tsx
@@ -24,6 +24,8 @@ export function AppBottomNav({
     <nav className={getRootClass(variant)} aria-label="Primary navigation">
       <button
         type="button"
+        data-analytics-key="navigation.chat"
+        data-analytics-label="Chat navigation"
         className={getButtonClass(activeItem === "chat")}
         aria-current={activeItem === "chat" ? "page" : undefined}
         onClick={onChatClick}
@@ -33,6 +35,8 @@ export function AppBottomNav({
       </button>
       <button
         type="button"
+        data-analytics-key="navigation.private_room"
+        data-analytics-label="Private room navigation"
         className={getButtonClass(activeItem === "privateRoom")}
         aria-current={activeItem === "privateRoom" ? "page" : undefined}
         onClick={onPrivateRoomClick}
diff --git a/src/app/_hooks/__tests__/use-payment-plan-analytics.test.tsx b/src/app/_hooks/__tests__/use-payment-plan-analytics.test.tsx
new file mode 100644
index 00000000..f2a7246c
--- /dev/null
+++ b/src/app/_hooks/__tests__/use-payment-plan-analytics.test.tsx
@@ -0,0 +1,82 @@
+import { act } from "react";
+import { createRoot, type Root } from "react-dom/client";
+import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
+
+import { PaymentPlan } from "@/data/dto/payment";
+import { behaviorAnalytics } from "@/lib/analytics";
+
+import { usePaymentPlanAnalytics } from "../use-payment-plan-analytics";
+
+const firstPlan = PaymentPlan.from({
+  planId: "plan-1",
+  planName: "Plan One",
+  orderType: "dol",
+  vipDays: null,
+  dolAmount: 100,
+  creditBalance: 100,
+  amountCents: 499,
+  originalAmountCents: null,
+  currency: "USD",
+});
+const secondPlan = PaymentPlan.from({
+  planId: "plan-2",
+  planName: "Plan Two",
+  orderType: "dol",
+  vipDays: null,
+  dolAmount: 250,
+  creditBalance: 250,
+  amountCents: 999,
+  originalAmountCents: null,
+  currency: "USD",
+});
+
+function Harness({ plans }: { plans: readonly PaymentPlan[] }) {
+  usePaymentPlanAnalytics(plans, {
+    entryPoint: "subscription_direct",
+    triggerReason: "manual_recharge",
+  });
+  return null;
+}
+
+describe("usePaymentPlanAnalytics", () => {
+  let container: HTMLDivElement;
+  let root: Root;
+
+  beforeEach(() => {
+    (globalThis as { IS_REACT_ACT_ENVIRONMENT?: boolean })
+      .IS_REACT_ACT_ENVIRONMENT = true;
+    container = document.createElement("div");
+    document.body.appendChild(container);
+    root = createRoot(container);
+  });
+
+  afterEach(() => {
+    act(() => root.unmount());
+    container.remove();
+    vi.restoreAllMocks();
+  });
+
+  it("tracks displayed order once per plan during a page mount", () => {
+    const impression = vi
+      .spyOn(behaviorAnalytics, "planImpression")
+      .mockImplementation(() => undefined);
+
+    act(() => root.render(<Harness plans={[firstPlan]} />));
+    act(() => root.render(<Harness plans={[firstPlan, secondPlan]} />));
+    act(() => root.render(<Harness plans={[firstPlan, secondPlan]} />));
+
+    expect(impression).toHaveBeenCalledTimes(2);
+    expect(impression).toHaveBeenNthCalledWith(
+      1,
+      firstPlan,
+      1,
+      expect.any(Object),
+    );
+    expect(impression).toHaveBeenNthCalledWith(
+      2,
+      secondPlan,
+      2,
+      expect.any(Object),
+    );
+  });
+});
diff --git a/src/app/_hooks/use-payment-launch-flow.ts b/src/app/_hooks/use-payment-launch-flow.ts
index 3e6702ec..d721cc74 100644
--- a/src/app/_hooks/use-payment-launch-flow.ts
+++ b/src/app/_hooks/use-payment-launch-flow.ts
@@ -8,6 +8,7 @@ import {
   isEzpayPayment,
   launchEzpayRedirect,
 } from "@/lib/payment/payment_launch";
+import { behaviorAnalytics } from "@/lib/analytics";
 import type {
   PendingPaymentReturnTo,
   PendingPaymentSubscriptionType,
@@ -52,6 +53,38 @@ export interface PaymentLaunchFlow {
   stripeClientSecret: string | null;
 }
 
+function trackPaymentCheckoutOpened(
+  payment: PaymentContextState,
+  checkoutUrl: string,
+): void {
+  const plan = payment.plans.find(
+    (item) => item.planId === payment.selectedPlanId,
+  );
+  if (!payment.currentOrderId || !plan) return;
+  behaviorAnalytics.checkoutOpened({
+    orderId: payment.currentOrderId,
+    plan,
+    payChannel: payment.payChannel,
+    checkoutUrl,
+  });
+}
+
+function trackPaymentCheckoutFailed(
+  payment: PaymentContextState,
+  reason: "missing_checkout_url" | "payment_redirect_failed",
+): void {
+  const plan = payment.plans.find(
+    (item) => item.planId === payment.selectedPlanId,
+  );
+  if (!payment.currentOrderId || !plan) return;
+  behaviorAnalytics.checkoutFailed({
+    orderId: payment.currentOrderId,
+    plan,
+    payChannel: payment.payChannel,
+    reason,
+  });
+}
+
 export function shouldShowEzpayConfirmation({
   currentOrderId,
   isProduction,
@@ -87,7 +120,6 @@ export function usePaymentLaunchFlow({
   const ezpayPaymentUrl = payment.payParams
     ? getPaymentUrl(payment.payParams)
     : null;
-
   useEffect(() => {
     if (!payment.payParams || payment.launchNonce <= launchedNonceRef.current) {
       return;
@@ -95,7 +127,10 @@ export function usePaymentLaunchFlow({
 
     launchedNonceRef.current = payment.launchNonce;
     const clientSecret = getStripeClientSecret(payment.payParams);
-    if (clientSecret) return;
+    if (clientSecret) {
+      trackPaymentCheckoutOpened(payment, "stripe_embedded");
+      return;
+    }
 
     const paymentUrl = getPaymentUrl(payment.payParams);
     if (paymentUrl) {
@@ -117,16 +152,29 @@ export function usePaymentLaunchFlow({
           subscriptionType,
           ...(tipCoffeeType ? { tipCoffeeType } : {}),
           ...(returnTo ? { returnTo } : {}),
-          onFailed: (errorMessage) =>
-            paymentDispatch({ type: "PaymentLaunchFailed", errorMessage }),
+          onOpened: () => trackPaymentCheckoutOpened(payment, paymentUrl),
+          onFailed: (errorMessage) => {
+            trackPaymentCheckoutFailed(payment, "payment_redirect_failed");
+            paymentDispatch({ type: "PaymentLaunchFailed", errorMessage });
+          },
         });
         return;
       }
 
-      window.location.href = paymentUrl;
+      try {
+        window.location.href = paymentUrl;
+        trackPaymentCheckoutOpened(payment, paymentUrl);
+      } catch {
+        trackPaymentCheckoutFailed(payment, "payment_redirect_failed");
+        paymentDispatch({
+          type: "PaymentLaunchFailed",
+          errorMessage: "Could not open the payment page. Please try again.",
+        });
+      }
       return;
     }
 
+    trackPaymentCheckoutFailed(payment, "missing_checkout_url");
     paymentDispatch({
       type: "PaymentLaunchFailed",
       errorMessage: UNSUPPORTED_PAYMENT_PARAMS_MESSAGE,
@@ -135,8 +183,12 @@ export function usePaymentLaunchFlow({
     log,
     logScope,
     payment.currentOrderId,
+    payment,
     payment.launchNonce,
+    payment.payChannel,
     payment.payParams,
+    payment.plans,
+    payment.selectedPlanId,
     paymentDispatch,
     returnTo,
     subscriptionType,
@@ -183,7 +235,9 @@ export function usePaymentLaunchFlow({
       subscriptionType,
       ...(tipCoffeeType ? { tipCoffeeType } : {}),
       ...(returnTo ? { returnTo } : {}),
+      onOpened: () => trackPaymentCheckoutOpened(payment, ezpayPaymentUrl),
       onFailed: (errorMessage) => {
+        trackPaymentCheckoutFailed(payment, "payment_redirect_failed");
         setIsConfirmingEzpay(false);
         paymentDispatch({ type: "PaymentLaunchFailed", errorMessage });
       },
diff --git a/src/app/_hooks/use-payment-plan-analytics.ts b/src/app/_hooks/use-payment-plan-analytics.ts
new file mode 100644
index 00000000..84105c94
--- /dev/null
+++ b/src/app/_hooks/use-payment-plan-analytics.ts
@@ -0,0 +1,29 @@
+"use client";
+
+import { useEffect, useRef } from "react";
+
+import type { PaymentPlan } from "@/data/dto/payment";
+import {
+  behaviorAnalytics,
+  type PaymentAnalyticsContext,
+} from "@/lib/analytics";
+
+export function usePaymentPlanAnalytics(
+  plans: readonly PaymentPlan[],
+  context: PaymentAnalyticsContext,
+): void {
+  const trackedRef = useRef(new Set<string>());
+  const { entryPoint, triggerReason } = context;
+
+  useEffect(() => {
+    plans.forEach((plan, index) => {
+      const key = `${entryPoint}:${triggerReason}:${plan.planId}`;
+      if (trackedRef.current.has(key)) return;
+      trackedRef.current.add(key);
+      behaviorAnalytics.planImpression(plan, index + 1, {
+        entryPoint,
+        triggerReason,
+      });
+    });
+  }, [entryPoint, plans, triggerReason]);
+}
diff --git a/src/app/auth/components/__tests__/tailwind-components.test.tsx b/src/app/auth/components/__tests__/tailwind-components.test.tsx
index aa00706f..fbbf3c36 100644
--- a/src/app/auth/components/__tests__/tailwind-components.test.tsx
+++ b/src/app/auth/components/__tests__/tailwind-components.test.tsx
@@ -52,6 +52,7 @@ describe("auth Tailwind components", () => {
     expect(html).toContain("w-full");
     expect(html).toContain("gap-md");
     expect(html).toContain("Login");
+    expect(html).toContain('data-analytics-key="auth.email_login"');
   });
 
   it("renders EmailRegisterForm with Tailwind form layout", () => {
@@ -62,6 +63,7 @@ describe("auth Tailwind components", () => {
     expect(html).toContain("w-full");
     expect(html).toContain("gap-md");
     expect(html).toContain("Register");
+    expect(html).toContain('data-analytics-key="auth.email_register"');
   });
 
   it("renders AuthBackground with Tailwind layout classes", () => {
@@ -128,6 +130,7 @@ describe("auth Tailwind components", () => {
     );
 
     expect(html).toContain("Login with Facebook");
+    expect(html).toContain('data-analytics-key="auth.facebook_login"');
     expect(html).toContain("bg-auth-surface");
     expect(html).toContain("enabled:hover:brightness-[0.97]");
     expect(html).toContain("Other Sign In Options");
diff --git a/src/app/auth/components/auth-email-panel.tsx b/src/app/auth/components/auth-email-panel.tsx
index d67ffa0d..ec701a9f 100644
--- a/src/app/auth/components/auth-email-panel.tsx
+++ b/src/app/auth/components/auth-email-panel.tsx
@@ -83,6 +83,9 @@ export function AuthEmailPanel({
 
       <button
         type="button"
+        data-analytics-key={
+          mode === "login" ? "auth.open_register" : "auth.open_email_login"
+        }
         className="self-center border-0 bg-transparent pt-md text-(length:--responsive-body) text-auth-text-primary underline underline-offset-[3px] transition-opacity duration-150 hover:opacity-80"
         onClick={() => setMode((m) => (m === "login" ? "register" : "login"))}
       >
@@ -93,6 +96,8 @@ export function AuthEmailPanel({
 
       <button
         type="button"
+        data-analytics-key="auth.open_other_options"
+        data-analytics-label="Open other sign-in options"
         className="self-center border-0 bg-transparent py-md text-(length:--responsive-body) text-auth-text-primary underline underline-offset-[3px] transition-opacity duration-150 hover:opacity-80"
         onClick={() => setShowOptions(true)}
       >
diff --git a/src/app/auth/components/auth-facebook-panel.tsx b/src/app/auth/components/auth-facebook-panel.tsx
index e16cdc68..e58db1fd 100644
--- a/src/app/auth/components/auth-facebook-panel.tsx
+++ b/src/app/auth/components/auth-facebook-panel.tsx
@@ -63,6 +63,8 @@ export function AuthFacebookPanel({
 
       <button
         type="button"
+        data-analytics-key="auth.facebook_login"
+        data-analytics-label="Facebook login"
         className="mt-md inline-flex min-h-(--auth-field-height) w-full cursor-pointer items-center justify-center gap-md rounded-full border-0 bg-auth-surface px-lg text-(length:--responsive-body) font-semibold text-auth-text-primary shadow-[0_2px_6px_rgba(0,0,0,0.06)] transition-[filter,transform,opacity] duration-150 enabled:hover:brightness-[0.97] enabled:active:scale-98 disabled:cursor-not-allowed disabled:opacity-60"
         onClick={() => handleFacebook()}
         disabled={isLoading}
@@ -87,6 +89,8 @@ export function AuthFacebookPanel({
 
       <button
         type="button"
+        data-analytics-key="auth.open_other_options"
+        data-analytics-label="Open other sign-in options"
         className="self-center border-0 bg-transparent py-md text-(length:--responsive-body) text-auth-text-primary underline underline-offset-[3px] transition-opacity duration-150 hover:opacity-80"
         onClick={() => setShowOptions(true)}
       >
diff --git a/src/app/auth/components/auth-other-options-dialog.tsx b/src/app/auth/components/auth-other-options-dialog.tsx
index 00f98461..81287bc3 100644
--- a/src/app/auth/components/auth-other-options-dialog.tsx
+++ b/src/app/auth/components/auth-other-options-dialog.tsx
@@ -52,6 +52,8 @@ export function AuthOtherOptionsDialog({
 
         {mode === "email" ? (
           <AuthSocialButton
+            data-analytics-key="auth.facebook_login"
+            data-analytics-label="Facebook login"
             icon={<AuthProviderIcon provider="facebook" />}
             onClick={() => {
               onClose();
@@ -64,6 +66,8 @@ export function AuthOtherOptionsDialog({
 
         {showNonProductionEmailOption ? (
           <AuthSocialButton
+            data-analytics-key="auth.open_email_login"
+            data-analytics-label="Email login option"
             icon={<MdEmail size={20} color="var(--color-auth-text-primary)" />}
             onClick={() => {
               onClose();
@@ -78,6 +82,8 @@ export function AuthOtherOptionsDialog({
           <div className="w-full">{googleSlot}</div>
         ) : (
           <AuthSocialButton
+            data-analytics-key="auth.google_login"
+            data-analytics-label="Google login"
             icon={<AuthProviderIcon provider="google" />}
             onClick={() => {
               onClose();
diff --git a/src/app/auth/components/auth-panel.tsx b/src/app/auth/components/auth-panel.tsx
index 39aab185..a7957985 100644
--- a/src/app/auth/components/auth-panel.tsx
+++ b/src/app/auth/components/auth-panel.tsx
@@ -29,7 +29,7 @@ export function AuthPanel() {
 
   return (
     <div className="relative flex min-h-0 w-full flex-auto flex-col">
-      <BackButton onClick={handleBack} />
+      <BackButton onClick={handleBack} analyticsKey="auth.back" />
 
       {state.authPanelMode === "facebook" ? (
         <AuthFacebookPanel onSwitchToEmail={switchToEmail} />
diff --git a/src/app/auth/components/email-login-form.tsx b/src/app/auth/components/email-login-form.tsx
index 51bf1187..c837e1e7 100644
--- a/src/app/auth/components/email-login-form.tsx
+++ b/src/app/auth/components/email-login-form.tsx
@@ -98,7 +98,12 @@ export function EmailLoginForm({
       />
       {/* 优先级：本地校验错误 > 后端 globalError（两个互斥场景：本地校验未过时，UI 不会再有 globalError） */}
       <AuthErrorMessage message={validationError ?? globalError ?? null} />
-      <AuthPrimaryButton type="submit" isLoading={isLoading}>
+      <AuthPrimaryButton
+        type="submit"
+        isLoading={isLoading}
+        data-analytics-key="auth.email_login"
+        data-analytics-label="Email login"
+      >
         Login
       </AuthPrimaryButton>
     </form>
diff --git a/src/app/auth/components/email-register-form.tsx b/src/app/auth/components/email-register-form.tsx
index 148f3da0..fb0aa0d9 100644
--- a/src/app/auth/components/email-register-form.tsx
+++ b/src/app/auth/components/email-register-form.tsx
@@ -147,7 +147,12 @@ export function EmailRegisterForm({
       />
       {/* 优先级：本地校验错误 > 后端 globalError */}
       <AuthErrorMessage message={validationError ?? globalError ?? null} />
-      <AuthPrimaryButton type="submit" isLoading={isLoading}>
+      <AuthPrimaryButton
+        type="submit"
+        isLoading={isLoading}
+        data-analytics-key="auth.email_register"
+        data-analytics-label="Email register"
+      >
         Register
       </AuthPrimaryButton>
     </form>
diff --git a/src/app/chat/components/__tests__/tailwind-components.test.tsx b/src/app/chat/components/__tests__/tailwind-components.test.tsx
index ffbc808c..88a250ba 100644
--- a/src/app/chat/components/__tests__/tailwind-components.test.tsx
+++ b/src/app/chat/components/__tests__/tailwind-components.test.tsx
@@ -96,6 +96,7 @@ describe("chat Tailwind components", () => {
     );
 
     expect(activeHtml).toContain('aria-label="Send message"');
+    expect(activeHtml).toContain('data-analytics-key="chat.send_message"');
     expect(activeHtml).toContain("size-(--chat-send-button-size,40px)");
     expect(activeHtml).toContain(
       "bg-[linear-gradient(to_right,var(--color-button-gradient-start,#ff67e0),var(--color-button-gradient-end,#ff52a2))]",
@@ -167,6 +168,8 @@ describe("chat Tailwind components", () => {
     expect(memberHtml).toContain('href="/splash"');
     expect(memberHtml).toContain('aria-label="Back to home"');
     expect(memberHtml).toContain('aria-label="Menu"');
+    expect(memberHtml).toContain('data-analytics-key="chat.open_menu"');
+    expect(memberHtml).toContain('data-analytics-key="chat.back_to_home"');
     expect(memberHtml).toContain("bg-[rgba(13,11,20,0.7)]");
     expect(memberHtml).toContain("size-(--responsive-icon-button-size,42px)");
   });
@@ -264,6 +267,7 @@ describe("chat Tailwind components", () => {
     expect(html).toContain("We found 3 locked messages");
     expect(html).toContain("Could not unlock history.");
     expect(html).toContain("Unlocking...");
+    expect(html).toContain('data-analytics-key="chat.unlock_history"');
     expect(html).toContain("text-(--color-pwa-button-text,#ffffff)");
     expect(html).toContain("disabled");
   });
@@ -302,6 +306,7 @@ describe("chat Tailwind components", () => {
     expect(html).toContain("text-(--color-pwa-button-text,#ffffff)");
     expect(html).toContain("bg-[linear-gradient(90deg,#ff67e0_0%,#ff52a2_100%)]");
     expect(html).toContain("Top up now");
+    expect(html).toContain('data-analytics-key="chat.topup"');
   });
 
 });
diff --git a/src/app/chat/components/browser-hint-overlay.tsx b/src/app/chat/components/browser-hint-overlay.tsx
index fd5cd53b..fcdfaa94 100644
--- a/src/app/chat/components/browser-hint-overlay.tsx
+++ b/src/app/chat/components/browser-hint-overlay.tsx
@@ -81,6 +81,8 @@ export function BrowserHintOverlay({
   return (
     <button
       type="button"
+      data-analytics-key="chat.external_browser_hint"
+      data-analytics-label="External browser hint"
       className={[
         OVERLAY_BASE_CLASS_NAME,
         isExpanded ? OVERLAY_EXPANDED_CLASS_NAME : OVERLAY_COLLAPSED_CLASS_NAME,
diff --git a/src/app/chat/components/chat-header.tsx b/src/app/chat/components/chat-header.tsx
index f3a84d92..90a7037d 100644
--- a/src/app/chat/components/chat-header.tsx
+++ b/src/app/chat/components/chat-header.tsx
@@ -25,6 +25,8 @@ export function ChatHeader({ isGuest, offerBanner }: ChatHeaderProps) {
       {isGuest ? (
         <button
           type="button"
+          data-analytics-key="chat.open_signup"
+          data-analytics-label="Open sign up"
           className="flex w-full cursor-pointer items-center justify-center gap-(--spacing-sm,8px) border-0 bg-(--color-accent,#f84d96) px-(--spacing-md,12px) py-(--spacing-sm,8px) text-center text-(length:--responsive-caption,var(--font-size-sm,12px)) font-medium text-white"
           onClick={() => navigator.openAuth(ROUTES.chat)}
           aria-label="Sign up to unlock more features"
@@ -46,10 +48,13 @@ export function ChatHeader({ isGuest, offerBanner }: ChatHeaderProps) {
             href={ROUTES.splash}
             variant="dark"
             ariaLabel="Back to home"
+            analyticsKey="chat.back_to_home"
           />
 
           <button
             type="button"
+            data-analytics-key="chat.open_menu"
+            data-analytics-label="Open chat menu"
             className="flex size-(--responsive-icon-button-size,42px) cursor-pointer items-center justify-center rounded-(--radius-full,999px) border border-[rgba(255,255,255,0.12)] bg-[rgba(13,11,20,0.7)] text-(--color-text-primary,#fff) shadow-[0_10px_24px_rgba(0,0,0,0.2)] backdrop-blur-md transition-[background,transform] duration-150 hover:bg-[rgba(28,24,39,0.82)] active:scale-96 focus-visible:outline-2 focus-visible:outline-offset-3 focus-visible:outline-[#f657a0]"
             onClick={() => navigator.push(ROUTES.sidebar)}
             aria-label="Menu"
diff --git a/src/app/chat/components/chat-insufficient-credits-banner.tsx b/src/app/chat/components/chat-insufficient-credits-banner.tsx
index 0da54223..7567f29b 100644
--- a/src/app/chat/components/chat-insufficient-credits-banner.tsx
+++ b/src/app/chat/components/chat-insufficient-credits-banner.tsx
@@ -69,6 +69,8 @@ export function ChatInsufficientCreditsBanner({
       ) : null}
       <button
         type="button"
+        data-analytics-key="chat.topup"
+        data-analytics-label="Top up chat credits"
         className="min-h-(--responsive-control-height,48px) w-full cursor-pointer rounded-full border-0 bg-[linear-gradient(135deg,#ffb8e0_0%,#f57ec0_100%)] px-(--responsive-card-padding-lg,24px) text-(length:--responsive-card-title,18px) font-bold text-white shadow-[0_2px_8px_rgba(0,0,0,0.15)] transition-[box-shadow,transform] duration-150 hover:shadow-[0_4px_12px_rgba(0,0,0,0.2)] active:scale-98"
         onClick={handleClick}
         aria-label={ctaLabel}
diff --git a/src/app/chat/components/chat-send-button.tsx b/src/app/chat/components/chat-send-button.tsx
index 56880a78..a00d81a5 100644
--- a/src/app/chat/components/chat-send-button.tsx
+++ b/src/app/chat/components/chat-send-button.tsx
@@ -29,6 +29,8 @@ export function ChatSendButton({
   return (
     <button
       type="button"
+      data-analytics-key="chat.send_message"
+      data-analytics-label="Send message"
       className={[
         "flex aspect-square size-(--chat-send-button-size,40px) shrink-0 cursor-pointer items-center justify-center rounded-full border-0 bg-(--color-button-gradient-end,#fc69df) text-white transition-[background,transform] duration-200 disabled:cursor-not-allowed disabled:opacity-40 focus-visible:bg-[linear-gradient(to_right,var(--color-button-gradient-start,#ff67e0),var(--color-button-gradient-end,#ff52a2))]",
         isActive
diff --git a/src/app/chat/components/first-recharge-offer-banner.tsx b/src/app/chat/components/first-recharge-offer-banner.tsx
index 16e8a8c4..dfb3f7bc 100644
--- a/src/app/chat/components/first-recharge-offer-banner.tsx
+++ b/src/app/chat/components/first-recharge-offer-banner.tsx
@@ -23,6 +23,8 @@ export function FirstRechargeOfferBanner({
     <section className={styles.banner} aria-label="First recharge offer">
       <button
         type="button"
+        data-analytics-key="chat.first_recharge_offer"
+        data-analytics-label="Open first recharge offer"
         className={styles.contentButton}
         onClick={onClick}
       >
diff --git a/src/app/chat/components/fullscreen-image-viewer.tsx b/src/app/chat/components/fullscreen-image-viewer.tsx
index c34aa5ca..7128cb86 100644
--- a/src/app/chat/components/fullscreen-image-viewer.tsx
+++ b/src/app/chat/components/fullscreen-image-viewer.tsx
@@ -68,6 +68,8 @@ export function FullscreenImageViewer({
         </button>
         <button
           type="button"
+          data-analytics-key="chat.unlock_message"
+          data-analytics-label="Unlock private image"
           className={styles.unlockButton}
           disabled={isUnlockingImagePaywall || !onUnlockImagePaywall}
           onClick={onUnlockImagePaywall}
diff --git a/src/app/chat/components/history-unlock-dialog.tsx b/src/app/chat/components/history-unlock-dialog.tsx
index c53a4ff6..dd98f8fe 100644
--- a/src/app/chat/components/history-unlock-dialog.tsx
+++ b/src/app/chat/components/history-unlock-dialog.tsx
@@ -53,6 +53,8 @@ export function HistoryUnlockDialog({
           </button>
           <button
             type="button"
+            data-analytics-key="chat.unlock_history"
+            data-analytics-label="Unlock chat history"
             className="flex min-h-(--pwa-button-height,44px) flex-auto cursor-pointer items-center justify-center rounded-(--radius-bottom-sheet,28px) border-0 bg-[linear-gradient(var(--color-button-gradient-start,#ff67e0),var(--color-button-gradient-end,#ff52a2))] text-(length:--responsive-body,var(--font-size-lg,16px)) font-semibold text-(--color-pwa-button-text,#ffffff) disabled:cursor-not-allowed disabled:opacity-72"
             onClick={onConfirm}
             disabled={isLoading}
diff --git a/src/app/chat/components/insufficient-credits-dialog.tsx b/src/app/chat/components/insufficient-credits-dialog.tsx
index bb4cca7b..11fff477 100644
--- a/src/app/chat/components/insufficient-credits-dialog.tsx
+++ b/src/app/chat/components/insufficient-credits-dialog.tsx
@@ -72,6 +72,8 @@ export function InsufficientCreditsDialog({
           </button>
           <button
             type="button"
+            data-analytics-key="chat.topup"
+            data-analytics-label="Top up chat credits"
             className="flex min-h-(--pwa-button-height,44px) flex-auto cursor-pointer items-center justify-center rounded-(--radius-bottom-sheet,28px) border-0 bg-[linear-gradient(90deg,#ff67e0_0%,#ff52a2_100%)] text-(length:--responsive-body,var(--font-size-lg,16px)) font-bold text-(--color-pwa-button-text,#ffffff) shadow-[0_6px_14px_rgba(246,87,160,0.28)] focus-visible:outline-2 focus-visible:outline-offset-3 focus-visible:outline-[#f657a0]"
             onClick={onConfirm}
           >
diff --git a/src/app/chat/components/locked-image-message-card.tsx b/src/app/chat/components/locked-image-message-card.tsx
index 15a4d24f..4df1756f 100644
--- a/src/app/chat/components/locked-image-message-card.tsx
+++ b/src/app/chat/components/locked-image-message-card.tsx
@@ -33,6 +33,8 @@ export function LockedImageMessageCard({
         </p>
         <button
           type="button"
+          data-analytics-key="chat.unlock_message"
+          data-analytics-label="Unlock private image"
           className="mt-(--spacing-md,12px) w-full cursor-pointer rounded-full border-0 bg-[linear-gradient(90deg,#ff67e0,#ff52a2)] px-(--spacing-md,12px) py-[clamp(9px,1.852vw,10px)] text-(length:--responsive-body,14px) font-bold text-white disabled:cursor-not-allowed disabled:opacity-65 focus-visible:outline-2 focus-visible:outline-offset-3 focus-visible:outline-[#f657a0]"
           disabled={isUnlocking || !onUnlock}
           onClick={onUnlock}
diff --git a/src/app/chat/components/private-message-card.tsx b/src/app/chat/components/private-message-card.tsx
index b6ddc528..0dade6fa 100644
--- a/src/app/chat/components/private-message-card.tsx
+++ b/src/app/chat/components/private-message-card.tsx
@@ -32,6 +32,8 @@ export function PrivateMessageCard({
       </p>
       <button
         type="button"
+        data-analytics-key="chat.unlock_message"
+        data-analytics-label="Unlock private message"
         className="mt-(--spacing-md,12px) w-full cursor-pointer rounded-full border-0 bg-[linear-gradient(90deg,#ff67e0,#ff52a2)] px-(--spacing-md,12px) py-[clamp(9px,1.852vw,10px)] text-(length:--responsive-body,14px) font-bold text-white disabled:cursor-not-allowed disabled:opacity-65 focus-visible:outline-2 focus-visible:outline-offset-3 focus-visible:outline-[#f657a0]"
         disabled={isUnlocking || !onUnlock}
         onClick={onUnlock}
diff --git a/src/app/chat/components/voice-bubble.tsx b/src/app/chat/components/voice-bubble.tsx
index b126e9cc..e1945c4d 100644
--- a/src/app/chat/components/voice-bubble.tsx
+++ b/src/app/chat/components/voice-bubble.tsx
@@ -124,6 +124,8 @@ export function VoiceBubble({
             </p>
             <button
               type="button"
+              data-analytics-key="chat.unlock_message"
+              data-analytics-label="Unlock voice message"
               className={styles.unlockButton}
               disabled={isUnlocking || !onUnlock}
               onClick={onUnlock}
diff --git a/src/app/chat/hooks/use-chat-message-limit-banner.ts b/src/app/chat/hooks/use-chat-message-limit-banner.ts
index 324c862e..a3604197 100644
--- a/src/app/chat/hooks/use-chat-message-limit-banner.ts
+++ b/src/app/chat/hooks/use-chat-message-limit-banner.ts
@@ -1,6 +1,9 @@
 "use client";
 
+import { useEffect, useRef } from "react";
+
 import type { LoginStatus } from "@/data/dto/auth";
+import { behaviorAnalytics } from "@/lib/analytics";
 import { ROUTES } from "@/router/routes";
 import { useAppNavigator } from "@/router/use-app-navigator";
 import type { ChatUpgradeReason } from "@/stores/chat/chat-state";
@@ -33,6 +36,27 @@ export function useChatMessageLimitBanner({
   const navigator = useAppNavigator();
   const isVip = useUserSelector((state) => state.context.isVip);
   const view = getInsufficientCreditsMessageLimitView(loginStatus);
+  const visible = shouldShowMessageLimitBanner({
+    upgradePromptVisible,
+    upgradeReason,
+  });
+  const trackedVisibleRef = useRef(false);
+
+  useEffect(() => {
+    if (!visible) {
+      trackedVisibleRef.current = false;
+      return;
+    }
+    if (trackedVisibleRef.current) return;
+    trackedVisibleRef.current = true;
+    behaviorAnalytics.paywallShown(
+      {
+        entryPoint: "chat_input",
+        triggerReason: "insufficient_credits",
+      },
+      { isVip },
+    );
+  }, [isVip, visible]);
 
   function unlock(): void {
     if (view.action === "auth") {
@@ -43,15 +67,16 @@ export function useChatMessageLimitBanner({
     navigator.openSubscription({
       type: getInsufficientCreditsSubscriptionType(isVip),
       returnTo: "chat",
+      analytics: {
+        entryPoint: "chat_input",
+        triggerReason: "insufficient_credits",
+      },
     });
   }
 
   return {
     ...view,
-    visible: shouldShowMessageLimitBanner({
-      upgradePromptVisible,
-      upgradeReason,
-    }),
+    visible,
     unlock,
   };
 }
diff --git a/src/app/chat/hooks/use-chat-unlock-navigation-flow.ts b/src/app/chat/hooks/use-chat-unlock-navigation-flow.ts
index 21a0f769..7f96a4f3 100644
--- a/src/app/chat/hooks/use-chat-unlock-navigation-flow.ts
+++ b/src/app/chat/hooks/use-chat-unlock-navigation-flow.ts
@@ -1,9 +1,10 @@
 "use client";
 
-import { useEffect } from "react";
+import { useEffect, useRef } from "react";
 import { shallowEqual } from "@xstate/react";
 
 import type { ChatLockType } from "@/data/schemas/chat";
+import { behaviorAnalytics } from "@/lib/analytics";
 import {
   consumePendingChatUnlock,
   peekPendingChatUnlock,
@@ -60,6 +61,7 @@ export function useChatUnlockNavigationFlow({
 }: UseChatUnlockNavigationFlowInput): UseChatUnlockNavigationFlowOutput {
   const navigator = useAppNavigator();
   const isVip = useUserSelector((state) => state.context.isVip);
+  const trackedPaywallRef = useRef<string | null>(null);
   const chatState = useChatSelector(
     (state) => ({
       historyLoaded: state.context.historyLoaded,
@@ -77,6 +79,22 @@ export function useChatUnlockNavigationFlow({
     enabled,
   });
 
+  useEffect(() => {
+    if (!unlockPaywallRequest) return;
+    const requestKey = `${unlockPaywallRequest.displayMessageId}:${unlockPaywallRequest.clientLockId ?? ""}`;
+    if (trackedPaywallRef.current === requestKey) return;
+    trackedPaywallRef.current = requestKey;
+    behaviorAnalytics.paywallShown(
+      {
+        entryPoint: "chat_unlock",
+        triggerReason: unlockPaywallRequest.promotion
+          ? "ad_landing"
+          : "insufficient_credits",
+      },
+      { isVip },
+    );
+  }, [isVip, unlockPaywallRequest]);
+
   useEffect(() => {
     if (!enabled) return;
     if (!chatState.historyLoaded || !navigator.isAuthenticatedUser) return;
@@ -172,6 +190,12 @@ export function useChatUnlockNavigationFlow({
       promotion: unlockPaywallRequest.promotion,
       returnUrl,
       type: getInsufficientCreditsSubscriptionType(isVip),
+      analytics: {
+        entryPoint: "chat_unlock",
+        triggerReason: unlockPaywallRequest.promotion
+          ? "ad_landing"
+          : "insufficient_credits",
+      },
     });
   }
 
diff --git a/src/app/chat/hooks/use-first-recharge-offer-banner.ts b/src/app/chat/hooks/use-first-recharge-offer-banner.ts
index a3c7044b..c49519ee 100644
--- a/src/app/chat/hooks/use-first-recharge-offer-banner.ts
+++ b/src/app/chat/hooks/use-first-recharge-offer-banner.ts
@@ -139,7 +139,14 @@ export function useFirstRechargeOfferBanner({
   }
 
   function claim(): void {
-    navigator.openSubscription({ type: "vip", returnTo: "chat" });
+    navigator.openSubscription({
+      type: "vip",
+      returnTo: "chat",
+      analytics: {
+        entryPoint: "chat_offer_banner",
+        triggerReason: "vip_cta",
+      },
+    });
   }
 
   return {
diff --git a/src/app/layout.tsx b/src/app/layout.tsx
index 2d063394..eb7dd4c1 100644
--- a/src/app/layout.tsx
+++ b/src/app/layout.tsx
@@ -1,6 +1,9 @@
 import type { Metadata, Viewport } from "next";
+import Script from "next/script";
 import { SerwistProvider } from "@serwist/turbopack/react";
 import { SessionProvider } from "@/providers/session-provider";
+import { BehaviorAnalyticsScripts } from "@/providers/behavior-analytics-scripts";
+import { getBehaviorAnalyticsEndpoint } from "@/lib/analytics/behavior_analytics_config";
 import { geistSans, geistMono, athelas } from "@/core/fonts";
 import "./globals.css";
 
@@ -43,6 +46,12 @@ export default function RootLayout({
       className={`${geistSans.variable} ${geistMono.variable} ${athelas.variable} h-full antialiased`}
     >
       <body className="min-h-full flex flex-col">
+        <Script id="cozsweet-analytics-config" strategy="beforeInteractive">
+          {`window.COZSWEET_ANALYTICS_ENDPOINT=${JSON.stringify(
+            getBehaviorAnalyticsEndpoint(),
+          )}`}
+        </Script>
+        <BehaviorAnalyticsScripts />
         {/* NextAuth SessionProvider：为所有客户端组件提供 useSession() 上下文 */}
         <SessionProvider>
           <RootProviders>
diff --git a/src/app/private-room/components/__tests__/private-album-card.test.tsx b/src/app/private-room/components/__tests__/private-album-card.test.tsx
index c012dcad..915ba8d6 100644
--- a/src/app/private-room/components/__tests__/private-album-card.test.tsx
+++ b/src/app/private-room/components/__tests__/private-album-card.test.tsx
@@ -61,6 +61,9 @@ describe("PrivateAlbumCard", () => {
     expect(html).toContain("8 photos");
     expect(html).toContain("A quiet morning by the water.");
     expect(html).toContain('aria-label="Open 8 private album photos"');
+    expect(html).toContain(
+      'data-analytics-key="private_album.open_gallery"',
+    );
   });
 
   it("uses the backend first image as the locked cover", () => {
@@ -80,6 +83,7 @@ describe("PrivateAlbumCard", () => {
     );
     expect(html).toContain("Only for you.");
     expect(html).toContain("320 credits");
+    expect(html).toContain('data-analytics-key="private_album.unlock"');
   });
 
   it("renders an empty cover when an unlocked album has no image", () => {
diff --git a/src/app/private-room/components/private-album-card.tsx b/src/app/private-room/components/private-album-card.tsx
index d4188447..257c7831 100644
--- a/src/app/private-room/components/private-album-card.tsx
+++ b/src/app/private-room/components/private-album-card.tsx
@@ -61,6 +61,8 @@ export function PrivateAlbumCard({
       {isLocked ? (
         <button
           type="button"
+          data-analytics-key="private_album.unlock"
+          data-analytics-label="Unlock private album"
           className={styles.lockedPreview}
           disabled={isUnlocking}
           onClick={onUnlock}
@@ -93,6 +95,8 @@ export function PrivateAlbumCard({
       ) : firstImageUrl ? (
         <button
           type="button"
+          data-analytics-key="private_album.open_gallery"
+          data-analytics-label="Open private album gallery"
           className={styles.mediaCover}
           onClick={onOpenGallery}
           aria-label={`Open ${photoCount} private album photos`}
diff --git a/src/app/private-room/components/unlock-confirm-dialog.tsx b/src/app/private-room/components/unlock-confirm-dialog.tsx
index 4d51ab3a..d5efc7a9 100644
--- a/src/app/private-room/components/unlock-confirm-dialog.tsx
+++ b/src/app/private-room/components/unlock-confirm-dialog.tsx
@@ -38,6 +38,8 @@ export function UnlockConfirmDialog({
           </button>
           <button
             type="button"
+            data-analytics-key="private_album.unlock_confirm"
+            data-analytics-label="Confirm private album unlock"
             className={styles.dialogPrimary}
             disabled={isUnlocking}
             onClick={onConfirm}
diff --git a/src/app/private-room/private-room-screen.tsx b/src/app/private-room/private-room-screen.tsx
index 4992e931..6130b3a5 100644
--- a/src/app/private-room/private-room-screen.tsx
+++ b/src/app/private-room/private-room-screen.tsx
@@ -109,7 +109,13 @@ export function PrivateRoomScreen() {
       navigator.openAuth(ROUTES.privateRoom);
       return;
     }
-    navigator.openSubscription({ type: "topup" });
+    navigator.openSubscription({
+      type: "topup",
+      analytics: {
+        entryPoint: "private_room",
+        triggerReason: "vip_cta",
+      },
+    });
   };
 
   const handleOpenGallery = (albumId: string) => {
@@ -171,6 +177,8 @@ export function PrivateRoomScreen() {
 
           <button
             type="button"
+            data-analytics-key="private_room.primary_cta"
+            data-analytics-label="Open private room top up"
             className={styles.primaryCta}
             onClick={handleTopUpClick}
           >
diff --git a/src/app/private-room/use-private-room-flow.ts b/src/app/private-room/use-private-room-flow.ts
index cb7ca57a..3474710f 100644
--- a/src/app/private-room/use-private-room-flow.ts
+++ b/src/app/private-room/use-private-room-flow.ts
@@ -4,6 +4,7 @@ import { type Dispatch, useEffect, useRef } from "react";
 
 import type { LoginStatus } from "@/data/dto/auth";
 import { useGuestLoginBootstrap } from "@/hooks/use-guest-login-bootstrap";
+import { behaviorAnalytics } from "@/lib/analytics";
 import { ROUTES } from "@/router/routes";
 import { useAppNavigator } from "@/router/use-app-navigator";
 import type { AuthEvent } from "@/stores/auth/auth-events";
@@ -84,7 +85,17 @@ export function usePrivateRoomUnlockPaywallNavigation({
     if (isPrivateRoomAuthRequired(loginStatus)) {
       navigator.openAuth(ROUTES.privateRoom);
     } else {
-      navigator.openSubscription({ type: "topup" });
+      behaviorAnalytics.paywallShown({
+        entryPoint: "private_album_unlock",
+        triggerReason: "insufficient_credits",
+      });
+      navigator.openSubscription({
+        type: "topup",
+        analytics: {
+          entryPoint: "private_album_unlock",
+          triggerReason: "insufficient_credits",
+        },
+      });
     }
     roomDispatch({ type: "PrivateRoomUnlockPaywallConsumed" });
   }, [loginStatus, navigator, roomDispatch, unlockPaywallRequest]);
diff --git a/src/app/sidebar/components/sidebar-wallet-card.tsx b/src/app/sidebar/components/sidebar-wallet-card.tsx
index cfe36943..2bb00ae7 100644
--- a/src/app/sidebar/components/sidebar-wallet-card.tsx
+++ b/src/app/sidebar/components/sidebar-wallet-card.tsx
@@ -45,6 +45,8 @@ export function SidebarWalletCard({
 
         <button
           type="button"
+          data-analytics-key="sidebar.coins_rules"
+          data-analytics-label="Open coin usage rules"
           className={styles.rulesButton}
           onClick={onRulesClick}
         >
@@ -56,13 +58,21 @@ export function SidebarWalletCard({
         {onActivateVip ? (
           <button
             type="button"
+            data-analytics-key="sidebar.activate_vip"
+            data-analytics-label="Activate VIP"
             className={styles.activateButton}
             onClick={onActivateVip}
           >
             Activate VIP
           </button>
         ) : null}
-        <button type="button" className={styles.topUpButton} onClick={onTopUp}>
+        <button
+          type="button"
+          data-analytics-key="sidebar.topup"
+          data-analytics-label="Top up credits"
+          className={styles.topUpButton}
+          onClick={onTopUp}
+        >
           Top Up
         </button>
       </div>
diff --git a/src/app/sidebar/components/user-header.tsx b/src/app/sidebar/components/user-header.tsx
index ac39a1d0..168137fe 100644
--- a/src/app/sidebar/components/user-header.tsx
+++ b/src/app/sidebar/components/user-header.tsx
@@ -80,6 +80,8 @@ export function UserHeader({
       {state === "guest" && (
         <button
           type="button"
+          data-analytics-key="sidebar.login"
+          data-analytics-label="Open login"
           className="inline-flex shrink-0 cursor-pointer items-center justify-center rounded-full border-0 bg-[linear-gradient(90deg,var(--color-button-gradient-start,#ff67e0),var(--color-button-gradient-end,#ff52a2))] px-(--spacing-lg,16px) py-[clamp(5px,1.111vw,6px)] text-(length:clamp(12px,2.593vw,14px)) font-semibold text-(--color-text-primary,#ffffff) hover:opacity-90 focus-visible:outline-2 focus-visible:outline-offset-2 focus-visible:outline-(--color-accent,#f84d96)"
           onClick={onLoginClick}
           aria-label="Log in"
diff --git a/src/app/sidebar/sidebar-screen.tsx b/src/app/sidebar/sidebar-screen.tsx
index e383f3c3..06066fc4 100644
--- a/src/app/sidebar/sidebar-screen.tsx
+++ b/src/app/sidebar/sidebar-screen.tsx
@@ -46,7 +46,11 @@ export function SidebarScreen() {
         <div className={styles.bgOrbTwo} aria-hidden="true" />
 
         <div className={styles.topBar}>
-          <BackButton href={ROUTES.chat} variant="soft" />
+          <BackButton
+            href={ROUTES.chat}
+            variant="soft"
+            analyticsKey="sidebar.back_to_chat"
+          />
         </div>
 
         <section className={`${styles.userSlot} ${styles.revealOne}`}>
@@ -68,10 +72,25 @@ export function SidebarScreen() {
             dailyFreePrivateRemaining={view.wallet.dailyFreePrivateRemaining}
             onActivateVip={
               view.canActivateVip
-                ? () => navigator.openSubscription({ type: "vip" })
+                ? () =>
+                    navigator.openSubscription({
+                      type: "vip",
+                      analytics: {
+                        entryPoint: "sidebar",
+                        triggerReason: "vip_cta",
+                      },
+                    })
                 : undefined
             }
-            onTopUp={() => navigator.openSubscription({ type: "topup" })}
+            onTopUp={() =>
+              navigator.openSubscription({
+                type: "topup",
+                analytics: {
+                  entryPoint: "sidebar",
+                  triggerReason: "sidebar_recharge",
+                },
+              })
+            }
             onRulesClick={() => navigator.push(ROUTES.coinsRules)}
           />
         </section>
@@ -103,6 +122,8 @@ export function SidebarScreen() {
 
               <button
                 type="button"
+                data-analytics-key="sidebar.logout"
+                data-analytics-label="Log out"
                 className={styles.logoutCard}
                 onClick={handleLogoutClick}
               >
diff --git a/src/app/splash/components/__tests__/tailwind-components.test.tsx b/src/app/splash/components/__tests__/tailwind-components.test.tsx
index 095ca0c9..c87998e6 100644
--- a/src/app/splash/components/__tests__/tailwind-components.test.tsx
+++ b/src/app/splash/components/__tests__/tailwind-components.test.tsx
@@ -46,6 +46,7 @@ describe("splash Tailwind components", () => {
     expect(html).toContain("active:enabled:brightness-90");
     expect(html).toContain("touch-manipulation");
     expect(html).toContain("Start Chatting");
+    expect(html).toContain('data-analytics-key="splash.start_chat"');
     expect(html).not.toContain("disabled=\"");
     expect(html).not.toContain("animate-spin");
   });
diff --git a/src/app/splash/components/splash-button.tsx b/src/app/splash/components/splash-button.tsx
index 43658a47..758a194f 100644
--- a/src/app/splash/components/splash-button.tsx
+++ b/src/app/splash/components/splash-button.tsx
@@ -11,6 +11,8 @@ export function SplashButton({ onStartChat }: SplashButtonProps) {
     <div className="z-2 flex w-full flex-row items-center justify-center gap-[clamp(var(--spacing-md,12px),4.815vw,var(--spacing-26,26px))] px-[clamp(var(--spacing-sm,8px),2.963vw,var(--spacing-lg,16px))]">
       <button
         type="button"
+        data-analytics-key="splash.start_chat"
+        data-analytics-label="Start chatting"
         onClick={onStartChat}
         className="inline-flex min-h-(--responsive-control-height,48px) w-full max-w-120 touch-manipulation flex-auto cursor-pointer items-center justify-center rounded-(--radius-full,999px) border-0 bg-[linear-gradient(to_right,var(--color-button-gradient-start),var(--color-button-gradient-end))] px-[clamp(var(--spacing-lg,16px),5.556vw,30px)] font-bold italic text-white shadow-[0_0_10px_rgba(248,89,168,0.3)] transition-[filter,box-shadow,transform] duration-150 ease-out [-webkit-tap-highlight-color:transparent] focus-visible:outline-2 focus-visible:outline-offset-3 focus-visible:outline-white enabled:hover:-translate-y-px enabled:hover:brightness-105 enabled:hover:shadow-[0_8px_22px_rgba(248,89,168,0.42)] active:enabled:translate-y-0.5 active:enabled:scale-96 active:enabled:brightness-90 active:enabled:shadow-[0_2px_6px_rgba(248,89,168,0.24)] motion-reduce:transition-none motion-reduce:active:enabled:transform-none disabled:cursor-not-allowed disabled:opacity-70"
       >
diff --git a/src/app/splash/components/splash-latest-message.tsx b/src/app/splash/components/splash-latest-message.tsx
index 43223293..3d9a5ee5 100644
--- a/src/app/splash/components/splash-latest-message.tsx
+++ b/src/app/splash/components/splash-latest-message.tsx
@@ -22,6 +22,8 @@ export function SplashLatestMessage({
   return (
     <button
       type="button"
+      data-analytics-key="splash.latest_message"
+      data-analytics-label="Open latest message"
       className={styles.card}
       onClick={onOpenChat}
       aria-label="Open latest message from Elio"
diff --git a/src/app/splash/splash-screen.tsx b/src/app/splash/splash-screen.tsx
index ebd9b50a..06723e0d 100644
--- a/src/app/splash/splash-screen.tsx
+++ b/src/app/splash/splash-screen.tsx
@@ -18,11 +18,6 @@ import {
 import { useSplashLatestMessage } from "./hooks/use-splash-latest-message";
 import styles from "./components/splash-screen.module.css";
 
-// 尽量早地缓存 beforeinstallprompt，避免用户停留 splash 时浏览器事件已触发并丢失。
-if (typeof window !== "undefined") {
-  pwaUtil.prepareInstallPrompt();
-}
-
 export function SplashScreen() {
   const navigator = useAppNavigator();
   const authState = useAuthState();
diff --git a/src/app/subscription/components/__tests__/tailwind-components.test.tsx b/src/app/subscription/components/__tests__/tailwind-components.test.tsx
index a5b5e4d3..6cf27cd5 100644
--- a/src/app/subscription/components/__tests__/tailwind-components.test.tsx
+++ b/src/app/subscription/components/__tests__/tailwind-components.test.tsx
@@ -66,6 +66,9 @@ describe("subscription Tailwind components", () => {
       /<button[^>]*aria-pressed="true"[^>]*>/,
     )?.[0];
     expect(selectedButton).toBeDefined();
+    expect(selectedButton).toContain(
+      'data-analytics-key="subscription.payment_method"',
+    );
     expect(selectedButton).toContain("border-[#f657a0]");
     expect(selectedButton).not.toContain("border-[rgba(246,87,160,0.18)]");
     expect(selectedButton).toContain("bg-[#fff4f9]");
diff --git a/src/app/subscription/components/subscription-checkout-button.tsx b/src/app/subscription/components/subscription-checkout-button.tsx
index e7c34e00..075658ab 100644
--- a/src/app/subscription/components/subscription-checkout-button.tsx
+++ b/src/app/subscription/components/subscription-checkout-button.tsx
@@ -67,6 +67,8 @@ export function SubscriptionCheckoutButton({
     <>
       <SubscriptionCtaButton
         type="button"
+        data-analytics-key="subscription.checkout"
+        data-analytics-label="Start subscription checkout"
         disabled={disabled}
         isLoading={isLoading}
         onClick={handleClick}
@@ -147,6 +149,8 @@ function EzpayRedirectConfirmDialog({
           </button>
           <button
             type="button"
+            data-analytics-key="subscription.external_checkout"
+            data-analytics-label="Continue to external checkout"
             className={`${dialogStyles.button} ${dialogStyles.primary}`}
             disabled={isConfirming}
             onClick={onConfirm}
diff --git a/src/app/subscription/components/subscription-coins-offer-section.tsx b/src/app/subscription/components/subscription-coins-offer-section.tsx
index f2b9ea11..eda0fbb9 100644
--- a/src/app/subscription/components/subscription-coins-offer-section.tsx
+++ b/src/app/subscription/components/subscription-coins-offer-section.tsx
@@ -40,6 +40,8 @@ export function SubscriptionCoinsOfferSection({
             <button
               key={plan.id}
               type="button"
+              data-analytics-key="subscription.plan_select"
+              data-analytics-label="Select coin plan"
               className={`${styles.row} ${selected ? styles.selected : ""}`}
               aria-pressed={selected}
               aria-label={`${plan.coins} Coins, ${plan.currency}${plan.price}`}
diff --git a/src/app/subscription/components/subscription-payment-method.tsx b/src/app/subscription/components/subscription-payment-method.tsx
index 46ce88e2..a2ba9acd 100644
--- a/src/app/subscription/components/subscription-payment-method.tsx
+++ b/src/app/subscription/components/subscription-payment-method.tsx
@@ -75,6 +75,8 @@ export function SubscriptionPaymentMethod({
             <button
               key={method.channel}
               type="button"
+              data-analytics-key="subscription.payment_method"
+              data-analytics-label="Select payment method"
               className={classes}
               disabled={disabled}
               aria-pressed={selected}
diff --git a/src/app/subscription/components/subscription-vip-offer-section.tsx b/src/app/subscription/components/subscription-vip-offer-section.tsx
index 63ef377d..17535e93 100644
--- a/src/app/subscription/components/subscription-vip-offer-section.tsx
+++ b/src/app/subscription/components/subscription-vip-offer-section.tsx
@@ -46,6 +46,8 @@ export function SubscriptionVipOfferSection({
             <button
               key={plan.id}
               type="button"
+              data-analytics-key="subscription.plan_select"
+              data-analytics-label="Select VIP plan"
               className={`${styles.planCard} ${selected ? styles.selected : ""}`}
               aria-pressed={selected}
               aria-label={`${plan.title}, ${plan.price} ${plan.currency}`}
diff --git a/src/app/subscription/subscription-page-client.tsx b/src/app/subscription/subscription-page-client.tsx
index d6a4bf85..e7011df5 100644
--- a/src/app/subscription/subscription-page-client.tsx
+++ b/src/app/subscription/subscription-page-client.tsx
@@ -3,6 +3,11 @@
 import { useSearchParams } from "next/navigation";
 
 import type { PayChannel } from "@/data/dto/payment";
+import {
+  PAYMENT_ANALYTICS_ENTRY_PARAM,
+  PAYMENT_ANALYTICS_REASON_PARAM,
+  parsePaymentAnalyticsContext,
+} from "@/lib/analytics";
 
 import {
   SubscriptionScreen,
@@ -28,6 +33,11 @@ export function SubscriptionPageClient() {
   const shouldResumePendingOrder = searchParams.get("paymentReturn") === "1";
   const returnTo = toReturnTo(searchParams.get("returnTo"));
   const initialPayChannel = toPayChannel(searchParams.get("payChannel"));
+  const analyticsContext = parsePaymentAnalyticsContext({
+    entryPoint: searchParams.get(PAYMENT_ANALYTICS_ENTRY_PARAM),
+    triggerReason: searchParams.get(PAYMENT_ANALYTICS_REASON_PARAM),
+    subscriptionType,
+  });
 
   return (
     <SubscriptionScreen
@@ -35,6 +45,7 @@ export function SubscriptionPageClient() {
       shouldResumePendingOrder={shouldResumePendingOrder}
       returnTo={returnTo}
       initialPayChannel={initialPayChannel}
+      analyticsContext={analyticsContext}
     />
   );
 }
diff --git a/src/app/subscription/subscription-screen.tsx b/src/app/subscription/subscription-screen.tsx
index 7f81ed11..82ab8e92 100644
--- a/src/app/subscription/subscription-screen.tsx
+++ b/src/app/subscription/subscription-screen.tsx
@@ -3,8 +3,14 @@ import { useEffect, useMemo, useRef } from "react";
 
 import { BackButton } from "@/app/_components";
 import { Checkbox, MobileShell } from "@/app/_components/core";
+import { usePaymentPlanAnalytics } from "@/app/_hooks/use-payment-plan-analytics";
 import { AppConstants } from "@/core/app_constants";
 import type { PayChannel } from "@/data/dto/payment";
+import {
+  behaviorAnalytics,
+  getDefaultPaymentAnalyticsContext,
+  type PaymentAnalyticsContext,
+} from "@/lib/analytics";
 import { useUserState } from "@/stores/user/user-context";
 
 import {
@@ -34,6 +40,7 @@ export interface SubscriptionScreenProps {
   shouldResumePendingOrder?: boolean;
   returnTo?: "chat" | null;
   initialPayChannel?: PayChannel | null;
+  analyticsContext?: PaymentAnalyticsContext;
 }
 
 export function SubscriptionScreen({
@@ -41,6 +48,7 @@ export function SubscriptionScreen({
   shouldResumePendingOrder = false,
   returnTo = null,
   initialPayChannel = null,
+  analyticsContext: providedAnalyticsContext,
 }: SubscriptionScreenProps) {
   const userState = useUserState();
   const countryCode = userState.currentUser?.countryCode;
@@ -64,6 +72,9 @@ export function SubscriptionScreen({
     initialPayChannel: resolvedInitialPayChannel,
   });
   const canSubscribeVip = subscriptionType === "vip";
+  const analyticsContext =
+    providedAnalyticsContext ??
+    getDefaultPaymentAnalyticsContext(subscriptionType);
 
   const vipOfferPlans = useMemo(
     () => toVipOfferPlanViews(payment.plans),
@@ -73,6 +84,17 @@ export function SubscriptionScreen({
     () => toCoinsOfferPlanViews(payment.plans),
     [payment.plans],
   );
+  const displayedPlans = useMemo(() => {
+    const displayedPlanIds = [
+      ...(canSubscribeVip ? vipOfferPlans : []),
+      ...directCoinsPlans,
+    ].map((plan) => plan.id);
+    return displayedPlanIds.flatMap((planId) => {
+      const plan = payment.plans.find((item) => item.planId === planId);
+      return plan ? [plan] : [];
+    });
+  }, [canSubscribeVip, directCoinsPlans, payment.plans, vipOfferPlans]);
+  usePaymentPlanAnalytics(displayedPlans, analyticsContext);
   const firstRechargeOffer = useMemo(
     () =>
       getFirstRechargeOfferView({
@@ -95,6 +117,12 @@ export function SubscriptionScreen({
   const canActivate =
     selectedPlan !== null && payment.agreed && !isPaymentBusy;
 
+  const handleSelectPlan = (planId: string) => {
+    const plan = payment.plans.find((item) => item.planId === planId);
+    if (plan) behaviorAnalytics.planClick(plan, analyticsContext);
+    paymentDispatch({ type: "PaymentPlanSelected", planId });
+  };
+
   useEffect(() => {
     if (isPaymentBusy) return;
 
@@ -160,6 +188,7 @@ export function SubscriptionScreen({
             className={styles.backSlot}
             onClick={handleBackClick}
             variant="soft"
+            analyticsKey="subscription.back"
           />
         </header>
 
@@ -187,23 +216,13 @@ export function SubscriptionScreen({
             <SubscriptionVipOfferSection
               plans={vipOfferPlans}
               selectedPlanId={payment.selectedPlanId || selectedPlan?.id || null}
-              onSelectPlan={(planId) =>
-                paymentDispatch({
-                  type: "PaymentPlanSelected",
-                  planId,
-                })
-              }
+              onSelectPlan={handleSelectPlan}
             />
           ) : null}
           <SubscriptionCoinsOfferSection
             plans={directCoinsPlans}
             selectedPlanId={payment.selectedPlanId || selectedPlan?.id || null}
-            onSelectPlan={(planId) =>
-              paymentDispatch({
-                type: "PaymentPlanSelected",
-                planId,
-              })
-            }
+            onSelectPlan={handleSelectPlan}
           />
         </div>
 
diff --git a/src/app/tip/tip-checkout-button.tsx b/src/app/tip/tip-checkout-button.tsx
index fd16bc1c..bd1df32b 100644
--- a/src/app/tip/tip-checkout-button.tsx
+++ b/src/app/tip/tip-checkout-button.tsx
@@ -54,6 +54,8 @@ export function TipCheckoutButton({
     <>
       <button
         type="button"
+        data-analytics-key="tip.checkout"
+        data-analytics-label="Buy coffee tip"
         className={styles.checkoutButton}
         disabled={disabled || isLoading}
         onClick={onOrder}
@@ -127,6 +129,8 @@ function EzpayRedirectConfirmDialog({
           </button>
           <button
             type="button"
+            data-analytics-key="tip.external_checkout"
+            data-analytics-label="Continue to external checkout"
             className={`${dialogStyles.button} ${dialogStyles.primary}`}
             disabled={isConfirming}
             onClick={onConfirm}
diff --git a/src/app/tip/tip-screen.tsx b/src/app/tip/tip-screen.tsx
index 6276f198..8585b930 100644
--- a/src/app/tip/tip-screen.tsx
+++ b/src/app/tip/tip-screen.tsx
@@ -7,7 +7,12 @@ import { ArrowLeft, Heart, Sparkles } from "lucide-react";
 import { CharacterAvatar } from "@/app/_components";
 import { MobileShell } from "@/app/_components/core";
 import { usePaymentOrderLifecycle } from "@/app/_hooks/use-payment-order-lifecycle";
+import { usePaymentPlanAnalytics } from "@/app/_hooks/use-payment-plan-analytics";
 import type { PayChannel } from "@/data/dto/payment";
+import {
+  behaviorAnalytics,
+  type PaymentAnalyticsContext,
+} from "@/lib/analytics";
 import {
   buildTipCoffeePath,
   DEFAULT_TIP_COFFEE_TYPE,
@@ -29,6 +34,11 @@ import {
 } from "./tip-screen.helpers";
 import styles from "./tip-screen.module.css";
 
+const TIP_ANALYTICS_CONTEXT: PaymentAnalyticsContext = {
+  entryPoint: "tip_page",
+  triggerReason: "ad_landing",
+};
+
 export interface TipScreenProps {
   coffeeType?: TipCoffeeType;
   shouldResumePendingOrder?: boolean;
@@ -55,6 +65,7 @@ export function TipScreen({
     [coffeeType, payment.plans],
   );
   const priceLabel = formatTipPrice(coffeePlan, coffeeType);
+  usePaymentPlanAnalytics(coffeePlan ? [coffeePlan] : [], TIP_ANALYTICS_CONTEXT);
   const isPaymentBusy =
     payment.isCreatingOrder || payment.isPollingOrder || payment.isPaid;
   const canCreateOrder =
@@ -136,6 +147,9 @@ export function TipScreen({
 
   const handleOrder = () => {
     if (isAuthLoading) return;
+    if (coffeePlan) {
+      behaviorAnalytics.planClick(coffeePlan, TIP_ANALYTICS_CONTEXT);
+    }
     if (!isRealLoginStatus(authState.loginStatus)) {
       navigator.openAuth(returnPath);
       return;
@@ -163,6 +177,8 @@ export function TipScreen({
         <header className={styles.header}>
           <button
             type="button"
+            data-analytics-key="tip.back"
+            data-analytics-label="Go back from tip"
             className={styles.backButton}
             aria-label="Go back"
             onClick={handleBack}
diff --git a/src/lib/analytics/__tests__/behavior_analytics.test.ts b/src/lib/analytics/__tests__/behavior_analytics.test.ts
new file mode 100644
index 00000000..14e74a47
--- /dev/null
+++ b/src/lib/analytics/__tests__/behavior_analytics.test.ts
@@ -0,0 +1,136 @@
+import { afterEach, describe, expect, it, vi } from "vitest";
+
+import { PaymentPlan } from "@/data/dto/payment";
+
+import {
+  behaviorAnalytics,
+  sanitizeAnalyticsCheckoutUrl,
+  type CozsweetBehaviorAnalyticsSdk,
+} from "../behavior_analytics";
+import {
+  getBehaviorAnalyticsBaseUrl,
+  getBehaviorAnalyticsEndpoint,
+  getBehaviorAnalyticsScriptUrl,
+} from "../behavior_analytics_config";
+
+function createSdkMock(): CozsweetBehaviorAnalyticsSdk {
+  return {
+    elementClick: vi.fn(),
+    paywallShown: vi.fn(),
+    rechargeModalOpen: vi.fn(),
+    planImpression: vi.fn(),
+    planClick: vi.fn(),
+    createOrderStart: vi.fn(),
+    createOrderSuccess: vi.fn(),
+    createOrderFailed: vi.fn(),
+    checkoutOpened: vi.fn(),
+    checkoutFailed: vi.fn(),
+    statusPollStart: vi.fn(),
+    statusPollUpdate: vi.fn(),
+    statusPollTimeout: vi.fn(),
+  };
+}
+
+const plan = PaymentPlan.from({
+  planId: "credits-100",
+  planName: "100 Credits",
+  orderType: "dol",
+  vipDays: null,
+  dolAmount: 100,
+  creditBalance: 100,
+  amountCents: 499,
+  originalAmountCents: null,
+  currency: "USD",
+});
+
+afterEach(() => {
+  delete window.CozsweetPaymentAnalytics;
+  vi.restoreAllMocks();
+});
+
+describe("behavior analytics configuration", () => {
+  it("uses production endpoints only for the production app environment", () => {
+    expect(getBehaviorAnalyticsBaseUrl("production")).toBe(
+      "https://api.banlv-ai.com",
+    );
+    expect(getBehaviorAnalyticsBaseUrl("development")).toBe(
+      "https://proapi.banlv-ai.com",
+    );
+    expect(getBehaviorAnalyticsBaseUrl("test")).toBe(
+      "https://proapi.banlv-ai.com",
+    );
+    expect(getBehaviorAnalyticsEndpoint("test")).toBe(
+      "https://proapi.banlv-ai.com/api/behavior/events",
+    );
+    expect(getBehaviorAnalyticsScriptUrl("production")).toBe(
+      "https://api.banlv-ai.com/js/cozsweet-payment-analytics.js",
+    );
+  });
+});
+
+describe("behavior analytics adapter", () => {
+  it("does nothing when the SDK is unavailable and swallows SDK errors", () => {
+    expect(() =>
+      behaviorAnalytics.planClick(plan, {
+        entryPoint: "subscription_direct",
+        triggerReason: "manual_recharge",
+      }),
+    ).not.toThrow();
+
+    const sdk = createSdkMock();
+    vi.mocked(sdk.planClick).mockImplementation(() => {
+      throw new Error("analytics unavailable");
+    });
+    window.CozsweetPaymentAnalytics = sdk;
+
+    expect(() =>
+      behaviorAnalytics.planClick(plan, {
+        entryPoint: "subscription_direct",
+        triggerReason: "manual_recharge",
+      }),
+    ).not.toThrow();
+  });
+
+  it("forwards payment context and strips checkout query parameters", () => {
+    const sdk = createSdkMock();
+    window.CozsweetPaymentAnalytics = sdk;
+
+    behaviorAnalytics.planClick(plan, {
+      entryPoint: "chat_unlock",
+      triggerReason: "insufficient_credits",
+    });
+    behaviorAnalytics.checkoutOpened({
+      orderId: "order-1",
+      plan,
+      payChannel: "stripe",
+      checkoutUrl:
+        "https://checkout.example/pay/session?client_secret=secret#payment",
+    });
+
+    expect(sdk.planClick).toHaveBeenCalledWith(
+      expect.objectContaining({ planId: "credits-100", amountCents: 499 }),
+      {
+        entryPoint: "chat_unlock",
+        triggerReason: "insufficient_credits",
+      },
+    );
+    expect(sdk.checkoutOpened).toHaveBeenCalledWith(
+      "order-1",
+      expect.objectContaining({ planId: "credits-100" }),
+      "stripe",
+      "https://checkout.example/pay/session",
+    );
+  });
+
+  it("uses a safe placeholder for invalid checkout urls", () => {
+    expect(sanitizeAnalyticsCheckoutUrl("stripe_embedded")).toBe(
+      "stripe_embedded",
+    );
+    expect(sanitizeAnalyticsCheckoutUrl("not a url")).toBe(
+      "external_checkout",
+    );
+    expect(sanitizeAnalyticsCheckoutUrl("javascript:alert('no')")).toBe(
+      "external_checkout",
+    );
+  });
+});
diff --git a/src/lib/analytics/__tests__/payment_analytics_context.test.ts b/src/lib/analytics/__tests__/payment_analytics_context.test.ts
new file mode 100644
index 00000000..f46c72e4
--- /dev/null
+++ b/src/lib/analytics/__tests__/payment_analytics_context.test.ts
@@ -0,0 +1,39 @@
+import { describe, expect, it } from "vitest";
+
+import {
+  getDefaultPaymentAnalyticsContext,
+  parsePaymentAnalyticsContext,
+} from "../payment_analytics_context";
+
+describe("payment analytics context", () => {
+  it("keeps supported payment entry and reason values", () => {
+    expect(
+      parsePaymentAnalyticsContext({
+        entryPoint: "chat_unlock",
+        triggerReason: "ad_landing",
+        subscriptionType: "topup",
+      }),
+    ).toEqual({
+      entryPoint: "chat_unlock",
+      triggerReason: "ad_landing",
+    });
+  });
+
+  it("falls back independently for invalid query values", () => {
+    expect(
+      parsePaymentAnalyticsContext({
+        entryPoint: "unsafe-entry",
+        triggerReason: "unsafe-reason",
+        subscriptionType: "topup",
+      }),
+    ).toEqual(getDefaultPaymentAnalyticsContext("topup"));
+
+    expect(
+      parsePaymentAnalyticsContext({
+        entryPoint: "sidebar",
+        triggerReason: null,
+        subscriptionType: "vip",
+      }),
+    ).toEqual({ entryPoint: "sidebar", triggerReason: "vip_cta" });
+  });
+});
diff --git a/src/lib/analytics/behavior_analytics.ts b/src/lib/analytics/behavior_analytics.ts
new file mode 100644
index 00000000..ebbabaa9
--- /dev/null
+++ b/src/lib/analytics/behavior_analytics.ts
@@ -0,0 +1,268 @@
+"use client";
+
+import type { PayChannel, PaymentPlan } from "@/data/dto/payment";
+
+import type {
+  PaymentAnalyticsContext,
+  PaymentAnalyticsEntryPoint,
+  PaymentAnalyticsTriggerReason,
+} from "./payment_analytics_context";
+
+export interface BehaviorAnalyticsPlan {
+  planId: string;
+  planName: string;
+  orderType: string;
+  amountCents: number;
+  currency: string;
+}
+
+export interface CozsweetBehaviorAnalyticsSdk {
+  elementClick(
+    key: string,
+    text: string,
+    metadata?: Record<string, unknown>,
+  ): void;
+  paywallShown(
+    triggerReason: PaymentAnalyticsTriggerReason,
+    metadata?: Record<string, unknown>,
+  ): void;
+  rechargeModalOpen(
+    entryPoint: PaymentAnalyticsEntryPoint,
+    triggerReason: PaymentAnalyticsTriggerReason,
+    metadata?: Record<string, unknown>,
+  ): void;
+  planImpression(
+    plan: BehaviorAnalyticsPlan,
+    position: number,
+    metadata?: Record<string, unknown>,
+  ): void;
+  planClick(
+    plan: BehaviorAnalyticsPlan,
+    metadata?: Record<string, unknown>,
+  ): void;
+  createOrderStart(
+    plan: BehaviorAnalyticsPlan,
+    payChannel: PayChannel,
+    metadata?: Record<string, unknown>,
+  ): void;
+  createOrderSuccess(
+    plan: BehaviorAnalyticsPlan,
+    orderId: string,
+    payChannel: PayChannel,
+    metadata?: Record<string, unknown>,
+  ): void;
+  createOrderFailed(
+    plan: BehaviorAnalyticsPlan,
+    reason: string,
+    payChannel: PayChannel,
+    metadata?: Record<string, unknown>,
+  ): void;
+  checkoutOpened(
+    orderId: string,
+    plan: BehaviorAnalyticsPlan,
+    payChannel: PayChannel,
+    checkoutUrl: string,
+    metadata?: Record<string, unknown>,
+  ): void;
+  checkoutFailed(
+    orderId: string,
+    plan: BehaviorAnalyticsPlan,
+    reason: string,
+    payChannel: PayChannel,
+    metadata?: Record<string, unknown>,
+  ): void;
+  statusPollStart(
+    orderId: string,
+    plan?: BehaviorAnalyticsPlan,
+    metadata?: Record<string, unknown>,
+  ): void;
+  statusPollUpdate(
+    orderId: string,
+    status: string,
+    plan?: BehaviorAnalyticsPlan,
+    metadata?: Record<string, unknown>,
+  ): void;
+  statusPollTimeout(
+    orderId: string,
+    plan?: BehaviorAnalyticsPlan,
+    metadata?: Record<string, unknown>,
+  ): void;
+}
+
+declare global {
+  interface Window {
+    COZSWEET_ANALYTICS_ENDPOINT?: string;
+    CozsweetPaymentAnalytics?: CozsweetBehaviorAnalyticsSdk;
+  }
+}
+
+export function toBehaviorAnalyticsPlan(
+  plan: PaymentPlan,
+): BehaviorAnalyticsPlan {
+  return {
+    planId: plan.planId,
+    planName: plan.planName,
+    orderType: plan.orderType,
+    amountCents: plan.amountCents,
+    currency: plan.currency,
+  };
+}
+
+export function sanitizeAnalyticsCheckoutUrl(value: string): string {
+  if (value === "stripe_embedded") return value;
+  try {
+    const url = new URL(value);
+    if (url.protocol !== "https:" && url.protocol !== "http:") {
+      return "external_checkout";
+    }
+    return `${url.origin}${url.pathname}`;
+  } catch {
+    return "external_checkout";
+  }
+}
+
+function invokeAnalytics(
+  callback: (analytics: CozsweetBehaviorAnalyticsSdk) => void,
+): void {
+  if (typeof window === "undefined") return;
+  const analytics = window.CozsweetPaymentAnalytics;
+  if (!analytics) return;
+  try {
+    callback(analytics);
+  } catch {
+    // Analytics must never interrupt user-facing flows.
+  }
+}
+
+export const behaviorAnalytics = {
+  elementClick(
+    key: string,
+    label: string,
+    metadata?: Record<string, unknown>,
+  ): void {
+    invokeAnalytics((analytics) =>
+      analytics.elementClick(key, label, metadata),
+    );
+  },
+  paywallShown(
+    context: PaymentAnalyticsContext,
+    metadata?: { isVip?: boolean },
+  ): void {
+    invokeAnalytics((analytics) =>
+      analytics.paywallShown(context.triggerReason, {
+        entryPoint: context.entryPoint,
+        ...metadata,
+      }),
+    );
+  },
+  rechargeModalOpen(context: PaymentAnalyticsContext): void {
+    invokeAnalytics((analytics) =>
+      analytics.rechargeModalOpen(
+        context.entryPoint,
+        context.triggerReason,
+      ),
+    );
+  },
+  planImpression(
+    plan: PaymentPlan,
+    position: number,
+    context: PaymentAnalyticsContext,
+  ): void {
+    invokeAnalytics((analytics) =>
+      analytics.planImpression(toBehaviorAnalyticsPlan(plan), position, {
+        ...context,
+      }),
+    );
+  },
+  planClick(plan: PaymentPlan, context: PaymentAnalyticsContext): void {
+    invokeAnalytics((analytics) =>
+      analytics.planClick(toBehaviorAnalyticsPlan(plan), { ...context }),
+    );
+  },
+  createOrderStart(plan: PaymentPlan, payChannel: PayChannel): void {
+    invokeAnalytics((analytics) =>
+      analytics.createOrderStart(toBehaviorAnalyticsPlan(plan), payChannel),
+    );
+  },
+  createOrderSuccess(
+    plan: PaymentPlan,
+    orderId: string,
+    payChannel: PayChannel,
+  ): void {
+    invokeAnalytics((analytics) =>
+      analytics.createOrderSuccess(
+        toBehaviorAnalyticsPlan(plan),
+        orderId,
+        payChannel,
+      ),
+    );
+  },
+  createOrderFailed(plan: PaymentPlan, payChannel: PayChannel): void {
+    invokeAnalytics((analytics) =>
+      analytics.createOrderFailed(
+        toBehaviorAnalyticsPlan(plan),
+        "create_order_error",
+        payChannel,
+      ),
+    );
+  },
+  checkoutOpened(input: {
+    orderId: string;
+    plan: PaymentPlan;
+    payChannel: PayChannel;
+    checkoutUrl: string;
+  }): void {
+    invokeAnalytics((analytics) =>
+      analytics.checkoutOpened(
+        input.orderId,
+        toBehaviorAnalyticsPlan(input.plan),
+        input.payChannel,
+        sanitizeAnalyticsCheckoutUrl(input.checkoutUrl),
+      ),
+    );
+  },
+  checkoutFailed(input: {
+    orderId: string;
+    plan: PaymentPlan;
+    payChannel: PayChannel;
+    reason: "missing_checkout_url" | "payment_redirect_failed";
+  }): void {
+    invokeAnalytics((analytics) =>
+      analytics.checkoutFailed(
+        input.orderId,
+        toBehaviorAnalyticsPlan(input.plan),
+        input.reason,
+        input.payChannel,
+      ),
+    );
+  },
+  statusPollStart(orderId: string, plan?: PaymentPlan): void {
+    invokeAnalytics((analytics) =>
+      analytics.statusPollStart(
+        orderId,
+        plan ? toBehaviorAnalyticsPlan(plan) : undefined,
+      ),
+    );
+  },
+  statusPollUpdate(
+    orderId: string,
+    status: string,
+    plan?: PaymentPlan,
+  ): void {
+    invokeAnalytics((analytics) =>
+      analytics.statusPollUpdate(
+        orderId,
+        status,
+        plan ? toBehaviorAnalyticsPlan(plan) : undefined,
+      ),
+    );
+  },
+  statusPollTimeout(orderId: string, plan?: PaymentPlan): void {
+    invokeAnalytics((analytics) =>
+      analytics.statusPollTimeout(
+        orderId,
+        plan ? toBehaviorAnalyticsPlan(plan) : undefined,
+      ),
+    );
+  },
+};
diff --git a/src/lib/analytics/behavior_analytics_config.ts b/src/lib/analytics/behavior_analytics_config.ts
new file mode 100644
index 00000000..f8b6fcae
--- /dev/null
+++ b/src/lib/analytics/behavior_analytics_config.ts
@@ -0,0 +1,18 @@
+const PRO_ANALYTICS_BASE_URL = "https://proapi.banlv-ai.com";
+const PRODUCTION_ANALYTICS_BASE_URL = "https://api.banlv-ai.com";
+
+export function getBehaviorAnalyticsBaseUrl(
+  appEnv = process.env.NEXT_PUBLIC_APP_ENV,
+): string {
+  return appEnv === "production"
+    ? PRODUCTION_ANALYTICS_BASE_URL
+    : PRO_ANALYTICS_BASE_URL;
+}
+
+export function getBehaviorAnalyticsEndpoint(appEnv?: string): string {
+  return `${getBehaviorAnalyticsBaseUrl(appEnv)}/api/behavior/events`;
+}
+
+export function getBehaviorAnalyticsScriptUrl(appEnv?: string): string {
+  return `${getBehaviorAnalyticsBaseUrl(appEnv)}/js/cozsweet-payment-analytics.js`;
+}
diff --git a/src/lib/analytics/index.ts b/src/lib/analytics/index.ts
new file mode 100644
index 00000000..19cf88cc
--- /dev/null
+++ b/src/lib/analytics/index.ts
@@ -0,0 +1,3 @@
+export * from "./behavior_analytics";
+export * from "./behavior_analytics_config";
+export * from "./payment_analytics_context";
diff --git a/src/lib/analytics/payment_analytics_context.ts b/src/lib/analytics/payment_analytics_context.ts
new file mode 100644
index 00000000..1a7bba7d
--- /dev/null
+++ b/src/lib/analytics/payment_analytics_context.ts
@@ -0,0 +1,80 @@
+export const PAYMENT_ANALYTICS_ENTRY_PARAM = "analytics_entry";
+export const PAYMENT_ANALYTICS_REASON_PARAM = "analytics_reason";
+
+export type PaymentAnalyticsTriggerReason =
+  | "daily_chat_limit"
+  | "private_topic_limit"
+  | "insufficient_credits"
+  | "sidebar_recharge"
+  | "vip_cta"
+  | "ad_landing"
+  | "manual_recharge"
+  | "unknown";
+
+export type PaymentAnalyticsEntryPoint =
+  | "chat_input"
+  | "chat_unlock"
+  | "private_album_unlock"
+  | "private_room"
+  | "sidebar"
+  | "chat_offer_banner"
+  | "subscription_direct"
+  | "tip_page"
+  | "external_entry"
+  | "unknown";
+
+export interface PaymentAnalyticsContext {
+  entryPoint: PaymentAnalyticsEntryPoint;
+  triggerReason: PaymentAnalyticsTriggerReason;
+}
+
+const ENTRY_POINTS = new Set<PaymentAnalyticsEntryPoint>([
+  "chat_input",
+  "chat_unlock",
+  "private_album_unlock",
+  "private_room",
+  "sidebar",
+  "chat_offer_banner",
+  "subscription_direct",
+  "tip_page",
+  "external_entry",
+  "unknown",
+]);
+
+const TRIGGER_REASONS = new Set<PaymentAnalyticsTriggerReason>([
+  "daily_chat_limit",
+  "private_topic_limit",
+  "insufficient_credits",
+  "sidebar_recharge",
+  "vip_cta",
+  "ad_landing",
+  "manual_recharge",
+  "unknown",
+]);
+
+export function getDefaultPaymentAnalyticsContext(
+  type: "vip" | "topup",
+): PaymentAnalyticsContext {
+  return {
+    entryPoint: "subscription_direct",
+    triggerReason: type === "topup" ? "manual_recharge" : "vip_cta",
+  };
+}
+
+export function parsePaymentAnalyticsContext(input: {
+  entryPoint: string | null;
+  triggerReason: string | null;
+  subscriptionType: "vip" | "topup";
+}): PaymentAnalyticsContext {
+  const fallback = getDefaultPaymentAnalyticsContext(input.subscriptionType);
+  return {
+    entryPoint: ENTRY_POINTS.has(input.entryPoint as PaymentAnalyticsEntryPoint)
+      ? (input.entryPoint as PaymentAnalyticsEntryPoint)
+      : fallback.entryPoint,
+    triggerReason: TRIGGER_REASONS.has(
+      input.triggerReason as PaymentAnalyticsTriggerReason,
+    )
+      ? (input.triggerReason as PaymentAnalyticsTriggerReason)
+      : fallback.triggerReason,
+  };
+}
diff --git a/src/lib/payment/__tests__/payment_launch.test.ts b/src/lib/payment/__tests__/payment_launch.test.ts
index de18abf6..53ebabae 100644
--- a/src/lib/payment/__tests__/payment_launch.test.ts
+++ b/src/lib/payment/__tests__/payment_launch.test.ts
@@ -1,9 +1,10 @@
-import { describe, expect, it } from "vitest";
+import { describe, expect, it, vi } from "vitest";
 
 import {
   getPaymentUrl,
   getStripeClientSecret,
   isEzpayPayment,
+  launchEzpayRedirect,
 } from "../payment_launch";
 
 describe("payment launch helpers", () => {
@@ -40,4 +41,22 @@ describe("payment launch helpers", () => {
       }),
     ).toBeNull();
   });
+
+  it("reports a launch failure before redirecting without an order id", async () => {
+    const onOpened = vi.fn();
+    const onFailed = vi.fn();
+
+    await launchEzpayRedirect({
+      orderId: null,
+      paymentUrl: "https://pay.example/checkout?token=secret",
+      subscriptionType: "topup",
+      onOpened,
+      onFailed,
+    });
+
+    expect(onOpened).not.toHaveBeenCalled();
+    expect(onFailed).toHaveBeenCalledWith(
+      "Missing order id before opening Ezpay.",
+    );
+  });
 });
diff --git a/src/lib/payment/payment_launch.ts b/src/lib/payment/payment_launch.ts
index 61d3ca96..704e8b8f 100644
--- a/src/lib/payment/payment_launch.ts
+++ b/src/lib/payment/payment_launch.ts
@@ -64,6 +64,7 @@ export interface LaunchEzpayRedirectInput {
   subscriptionType: PendingPaymentSubscriptionType;
   tipCoffeeType?: PendingPaymentTipCoffeeType;
   returnTo?: PendingPaymentReturnTo;
+  onOpened?: () => void;
   onFailed: (errorMessage: string) => void;
 }
 
@@ -73,6 +74,7 @@ export async function launchEzpayRedirect({
   subscriptionType,
   tipCoffeeType,
   returnTo,
+  onOpened,
   onFailed,
 }: LaunchEzpayRedirectInput): Promise<void> {
   log.debug("[payment-launch] launchEzpayRedirect START", {
@@ -121,5 +123,10 @@ export async function launchEzpayRedirect({
     subscriptionType,
     paymentUrl,
   });
-  window.location.href = paymentUrl;
+  try {
+    window.location.href = paymentUrl;
+    onOpened?.();
+  } catch {
+    onFailed("Could not open Ezpay. Please try again.");
+  }
 }
diff --git a/src/providers/behavior-analytics-scripts.tsx b/src/providers/behavior-analytics-scripts.tsx
new file mode 100644
index 00000000..00ed95f6
--- /dev/null
+++ b/src/providers/behavior-analytics-scripts.tsx
@@ -0,0 +1,15 @@
+import Script from "next/script";
+
+import { getBehaviorAnalyticsScriptUrl } from "@/lib/analytics/behavior_analytics_config";
+
+export function BehaviorAnalyticsScripts() {
+  const scriptUrl = getBehaviorAnalyticsScriptUrl();
+
+  return (
+    <Script
+      id="cozsweet-behavior-analytics"
+      src={scriptUrl}
+      strategy="afterInteractive"
+    />
+  );
+}
diff --git a/src/router/__tests__/navigation-resolver.test.ts b/src/router/__tests__/navigation-resolver.test.ts
index 5c6ee8b4..271203d6 100644
--- a/src/router/__tests__/navigation-resolver.test.ts
+++ b/src/router/__tests__/navigation-resolver.test.ts
@@ -33,6 +33,27 @@ describe("navigation resolver", () => {
     ).toBe("/subscription?type=topup");
   });
 
+  it("preserves payment analytics context through auth redirects", () => {
+    const subscriptionUrl = ROUTE_BUILDERS.subscription("topup", {
+      payChannel: "stripe",
+      returnTo: "chat",
+      analytics: {
+        entryPoint: "chat_unlock",
+        triggerReason: "ad_landing",
+      },
+    });
+
+    expect(subscriptionUrl).toBe(
+      "/subscription?type=topup&payChannel=stripe&returnTo=chat&analytics_entry=chat_unlock&analytics_reason=ad_landing",
+    );
+    expect(
+      resolveAuthenticatedNavigation({
+        loginStatus: "guest",
+        targetUrl: subscriptionUrl,
+      }),
+    ).toBe(ROUTE_BUILDERS.authWithRedirect(subscriptionUrl));
+  });
+
   it("allows not logged in users to enter chat for guest bootstrap", () => {
     expect(
       resolveRouteGuardRedirect({
diff --git a/src/router/navigation-types.ts b/src/router/navigation-types.ts
index c1c03659..9ad2c027 100644
--- a/src/router/navigation-types.ts
+++ b/src/router/navigation-types.ts
@@ -1,4 +1,5 @@
 import type { PayChannel } from "@/data/dto/payment";
+import type { PaymentAnalyticsContext } from "@/lib/analytics/payment_analytics_context";
 import type {
   PendingChatUnlockKind,
   PendingChatPromotion,
@@ -13,6 +14,7 @@ export interface OpenSubscriptionInput {
   payChannel?: PayChannel;
   returnTo?: AppSubscriptionReturnTo;
   replace?: boolean;
+  analytics?: PaymentAnalyticsContext;
 }
 
 export interface StartMessageUnlockInput {
@@ -37,4 +39,5 @@ export interface OpenSubscriptionForPendingUnlockInput {
   returnUrl: string;
   type: AppSubscriptionType;
   payChannel?: PayChannel;
+  analytics?: PaymentAnalyticsContext;
 }
diff --git a/src/router/routes.ts b/src/router/routes.ts
index 3123aa0a..3bcb0b4e 100644
--- a/src/router/routes.ts
+++ b/src/router/routes.ts
@@ -8,6 +8,11 @@
  */
 
 import type { PayChannel } from "@/data/dto/payment";
+import {
+  PAYMENT_ANALYTICS_ENTRY_PARAM,
+  PAYMENT_ANALYTICS_REASON_PARAM,
+  type PaymentAnalyticsContext,
+} from "@/lib/analytics/payment_analytics_context";
 
 /** 静态路由字面量 */
 export const ROUTES = {
@@ -29,11 +34,25 @@ export type StaticRoute = (typeof ROUTES)[keyof typeof ROUTES];
 export const ROUTE_BUILDERS = {
   subscription: (
     type: "vip" | "topup",
-    options: { payChannel?: PayChannel; returnTo?: "chat" } = {},
+    options: {
+      payChannel?: PayChannel;
+      returnTo?: "chat";
+      analytics?: PaymentAnalyticsContext;
+    } = {},
   ): `/subscription?${string}` => {
     const params = new URLSearchParams({ type });
     if (options.payChannel) params.set("payChannel", options.payChannel);
     if (options.returnTo) params.set("returnTo", options.returnTo);
+    if (options.analytics) {
+      params.set(
+        PAYMENT_ANALYTICS_ENTRY_PARAM,
+        options.analytics.entryPoint,
+      );
+      params.set(
+        PAYMENT_ANALYTICS_REASON_PARAM,
+        options.analytics.triggerReason,
+      );
+    }
     return `${ROUTES.subscription}?${params.toString()}` as const;
   },
   authWithRedirect: (redirectTo: string): `/auth?redirect=${string}` =>
diff --git a/src/router/use-app-navigator.ts b/src/router/use-app-navigator.ts
index aa4d01b1..74882fea 100644
--- a/src/router/use-app-navigator.ts
+++ b/src/router/use-app-navigator.ts
@@ -10,6 +10,10 @@ import {
   peekSubscriptionExplicitExitUrl,
 } from "@/lib/navigation/subscription_exit";
 import { getDefaultPayChannelForCountryCode } from "@/lib/payment/default_pay_channel";
+import {
+  behaviorAnalytics,
+  getDefaultPaymentAnalyticsContext,
+} from "@/lib/analytics";
 import { useAuthSelector } from "@/stores/auth/auth-context";
 import { useUserSelector } from "@/stores/user/user-context";
 
@@ -88,12 +92,16 @@ export function useAppNavigator(): AppNavigator {
       payChannel = getDefaultPayChannel(),
       returnTo = null,
       replace: shouldReplace = false,
+      analytics = getDefaultPaymentAnalyticsContext(type),
     }: OpenSubscriptionInput): void => {
       const target = ROUTE_BUILDERS.subscription(type, {
         payChannel,
         returnTo: returnTo ?? undefined,
+        analytics,
       });
 
+      behaviorAnalytics.rechargeModalOpen(analytics);
+
       const nextUrl = resolveAuthenticatedNavigation({
         loginStatus,
         targetUrl: target,
@@ -153,6 +161,7 @@ export function useAppNavigator(): AppNavigator {
       returnUrl,
       type,
       payChannel = getDefaultPayChannel(),
+      analytics,
     }: OpenSubscriptionForPendingUnlockInput): void => {
       void (async () => {
         await NavigationStorage.savePendingChatUnlock({
@@ -169,6 +178,7 @@ export function useAppNavigator(): AppNavigator {
           type,
           payChannel,
           returnTo: "chat",
+          analytics,
         });
       })();
     },
diff --git a/src/stores/payment/__tests__/payment-machine.test.ts b/src/stores/payment/__tests__/payment-machine.test.ts
index 6581c40e..a6abdeb3 100644
--- a/src/stores/payment/__tests__/payment-machine.test.ts
+++ b/src/stores/payment/__tests__/payment-machine.test.ts
@@ -7,6 +7,7 @@ import {
   PaymentOrderStatusResponse,
   PaymentPlansResponse,
 } from "@/data/dto/payment";
+import { behaviorAnalytics } from "@/lib/analytics";
 import { paymentMachine } from "@/stores/payment/payment-machine";
 import {
   MAX_ORDER_POLLING_MS,
@@ -94,6 +95,7 @@ const tipPlan = {
 function createTestPaymentMachine(
   overrides: Partial<{
     createOrderSpy: CreateOrderSpy;
+    createOrderError: Error;
     orderStatus: "pending" | "paid" | "failed";
     orderStatuses: Array<"pending" | "paid" | "failed">;
   }> = {},
@@ -124,6 +126,7 @@ function createTestPaymentMachine(
         CreateOrderInput
       >(async ({ input }) => {
         createOrderSpy(input);
+        if (overrides.createOrderError) throw overrides.createOrderError;
         return CreatePaymentOrderResponse.from({
           orderId: "pay_test_001",
           payParams: {
@@ -152,6 +155,7 @@ function createTestPaymentMachine(
 describe("paymentMachine", () => {
   afterEach(() => {
     vi.useRealTimers();
+    vi.restoreAllMocks();
   });
 
   it("loads plans and selects the default monthly VIP plan", async () => {
@@ -460,6 +464,18 @@ describe("paymentMachine", () => {
   });
 
   it("creates an order, polls it, and reaches paid state", async () => {
+    const createOrderStart = vi
+      .spyOn(behaviorAnalytics, "createOrderStart")
+      .mockImplementation(() => undefined);
+    const createOrderSuccess = vi
+      .spyOn(behaviorAnalytics, "createOrderSuccess")
+      .mockImplementation(() => undefined);
+    const statusPollStart = vi
+      .spyOn(behaviorAnalytics, "statusPollStart")
+      .mockImplementation(() => undefined);
+    const statusPollUpdate = vi
+      .spyOn(behaviorAnalytics, "statusPollUpdate")
+      .mockImplementation(() => undefined);
     const createOrderSpy = vi.fn<CreateOrderSpy>();
     const actor = createActor(
       createTestPaymentMachine({ createOrderSpy }),
@@ -481,6 +497,50 @@ describe("paymentMachine", () => {
     expect(context.orderStatus).toBe("paid");
     expect(context.orderPollingStartedAt).toBeNull();
     expect(context.launchNonce).toBe(1);
+    expect(createOrderStart).toHaveBeenCalledWith(
+      expect.objectContaining({ planId: "vip_monthly" }),
+      "stripe",
+    );
+    expect(createOrderSuccess).toHaveBeenCalledWith(
+      expect.objectContaining({ planId: "vip_monthly" }),
+      "pay_test_001",
+      "stripe",
+    );
+    expect(statusPollStart).toHaveBeenCalledWith(
+      "pay_test_001",
+      expect.objectContaining({ planId: "vip_monthly" }),
+    );
+    expect(statusPollUpdate).toHaveBeenCalledWith(
+      "pay_test_001",
+      "paid",
+      expect.objectContaining({ planId: "vip_monthly" }),
+    );
+
+    actor.stop();
+  });
+
+  it("tracks order creation failures without interrupting failure handling", async () => {
+    const createOrderFailed = vi
+      .spyOn(behaviorAnalytics, "createOrderFailed")
+      .mockImplementation(() => undefined);
+    const actor = createActor(
+      createTestPaymentMachine({
+        createOrderError: new Error("backend unavailable"),
+      }),
+    ).start();
+
+    actor.send({ type: "PaymentInit" });
+    await waitFor(actor, (snapshot) => snapshot.matches("ready"));
+    actor.send({ type: "PaymentCreateOrderSubmitted" });
+    await waitFor(actor, (snapshot) => snapshot.matches("failed"));
+
+    expect(createOrderFailed).toHaveBeenCalledWith(
+      expect.objectContaining({ planId: "vip_monthly" }),
+      "stripe",
+    );
+    expect(actor.getSnapshot().context.errorMessage).toBe(
+      "backend unavailable",
+    );
 
     actor.stop();
   });
@@ -533,6 +593,9 @@ describe("paymentMachine", () => {
   });
 
   it("moves to failed state when a pending order exceeds polling timeout", async () => {
+    const statusPollTimeout = vi
+      .spyOn(behaviorAnalytics, "statusPollTimeout")
+      .mockImplementation(() => undefined);
     const now = new Date("2026-06-30T00:00:00.000Z");
     vi.useFakeTimers();
     vi.setSystemTime(now);
@@ -555,6 +618,10 @@ describe("paymentMachine", () => {
     expect(context.orderStatus).toBe("failed");
     expect(context.orderPollingStartedAt).toBeNull();
     expect(context.errorMessage).toBe(PAYMENT_TIMEOUT_ERROR_MESSAGE);
+    expect(statusPollTimeout).toHaveBeenCalledWith(
+      "pay_test_001",
+      expect.objectContaining({ planId: "vip_monthly" }),
+    );
 
     actor.stop();
   });
diff --git a/src/stores/payment/payment-machine.helpers.ts b/src/stores/payment/payment-machine.helpers.ts
index e81c3116..fad18e34 100644
--- a/src/stores/payment/payment-machine.helpers.ts
+++ b/src/stores/payment/payment-machine.helpers.ts
@@ -179,6 +179,7 @@ export function selectPlanState(
 export function resetOrderState(): Partial<PaymentState> {
   return {
     currentOrderId: null,
+    currentOrderPlanId: null,
     payParams: null,
     orderStatus: null,
     orderPollingStartedAt: null,
diff --git a/src/stores/payment/payment-machine.ts b/src/stores/payment/payment-machine.ts
index b88cd994..dfbe801a 100644
--- a/src/stores/payment/payment-machine.ts
+++ b/src/stores/payment/payment-machine.ts
@@ -3,6 +3,7 @@
  */
 import { assign, setup } from "xstate";
 
+import { behaviorAnalytics } from "@/lib/analytics";
 import type { PaymentEvent } from "./payment-events";
 import { initialState, type PaymentState } from "./payment-state";
 import {
@@ -28,6 +29,19 @@ export { initialState } from "./payment-state";
 
 const POLL_DELAY_MS = 4000;
 
+function getSelectedPlan(context: PaymentState) {
+  return context.plans.find(
+    (plan) => plan.planId === context.selectedPlanId,
+  );
+}
+
+function getCurrentOrderPlan(context: PaymentState) {
+  if (!context.currentOrderPlanId) return undefined;
+  return context.plans.find(
+    (plan) => plan.planId === context.currentOrderPlanId,
+  );
+}
+
 export const paymentMachine = setup({
   types: {
     context: {} as PaymentState,
@@ -192,6 +206,10 @@ export const paymentMachine = setup({
     },
 
     creatingOrder: {
+      entry: ({ context }) => {
+        const plan = getSelectedPlan(context);
+        if (plan) behaviorAnalytics.createOrderStart(plan, context.payChannel);
+      },
       invoke: {
         src: "createOrder",
         input: ({ context }) => ({
@@ -201,20 +219,45 @@ export const paymentMachine = setup({
         }),
         onDone: {
           target: "pollingOrder",
-          actions: assign(({ context, event }) => ({
-            currentOrderId: event.output.orderId,
-            payParams: event.output.payParams,
-            orderStatus: "pending",
-            orderPollingStartedAt: Date.now(),
-            errorMessage: null,
-            launchNonce: context.launchNonce + 1,
-          })),
+          actions: [
+            ({ context, event }) => {
+              const plan = getSelectedPlan(context);
+              if (plan) {
+                behaviorAnalytics.createOrderSuccess(
+                  plan,
+                  event.output.orderId,
+                  context.payChannel,
+                );
+              }
+              behaviorAnalytics.statusPollStart(
+                event.output.orderId,
+                plan,
+              );
+            },
+            assign(({ context, event }) => ({
+              currentOrderId: event.output.orderId,
+              currentOrderPlanId: context.selectedPlanId,
+              payParams: event.output.payParams,
+              orderStatus: "pending",
+              orderPollingStartedAt: Date.now(),
+              errorMessage: null,
+              launchNonce: context.launchNonce + 1,
+            })),
+          ],
         },
         onError: {
           target: "failed",
-          actions: assign(({ event }) => ({
-            errorMessage: toPaymentErrorMessage(event.error),
-          })),
+          actions: [
+            ({ context }) => {
+              const plan = getSelectedPlan(context);
+              if (plan) {
+                behaviorAnalytics.createOrderFailed(plan, context.payChannel);
+              }
+            },
+            assign(({ event }) => ({
+              errorMessage: toPaymentErrorMessage(event.error),
+            })),
+          ],
         },
       },
     },
@@ -229,37 +272,73 @@ export const paymentMachine = setup({
           {
             guard: ({ event }) => event.output.status === "paid",
             target: "paid",
-            actions: assign(({ event }) => ({
-              orderStatus: event.output.status,
-              orderPollingStartedAt: null,
-              errorMessage: null,
-            })),
+            actions: [
+              ({ context, event }) =>
+                behaviorAnalytics.statusPollUpdate(
+                  context.currentOrderId ?? "",
+                  event.output.status,
+                  getCurrentOrderPlan(context),
+                ),
+              assign(({ event }) => ({
+                orderStatus: event.output.status,
+                orderPollingStartedAt: null,
+                errorMessage: null,
+              })),
+            ],
           },
           {
             guard: ({ event }) => event.output.status === "failed",
             target: "failed",
-            actions: assign(({ event }) => ({
-              orderStatus: event.output.status,
-              orderPollingStartedAt: null,
-              errorMessage: "Payment failed or was cancelled.",
-            })),
+            actions: [
+              ({ context, event }) =>
+                behaviorAnalytics.statusPollUpdate(
+                  context.currentOrderId ?? "",
+                  event.output.status,
+                  getCurrentOrderPlan(context),
+                ),
+              assign(({ event }) => ({
+                orderStatus: event.output.status,
+                orderPollingStartedAt: null,
+                errorMessage: "Payment failed or was cancelled.",
+              })),
+            ],
           },
           {
             guard: ({ context }) =>
               hasOrderPollingTimedOut(context.orderPollingStartedAt),
             target: "failed",
-            actions: assign({
-              orderStatus: "failed",
-              orderPollingStartedAt: null,
-              errorMessage: PAYMENT_TIMEOUT_ERROR_MESSAGE,
-            }),
+            actions: [
+              ({ context, event }) => {
+                const orderId = context.currentOrderId ?? "";
+                const plan = getCurrentOrderPlan(context);
+                behaviorAnalytics.statusPollUpdate(
+                  orderId,
+                  event.output.status,
+                  plan,
+                );
+                behaviorAnalytics.statusPollTimeout(orderId, plan);
+              },
+              assign({
+                orderStatus: "failed",
+                orderPollingStartedAt: null,
+                errorMessage: PAYMENT_TIMEOUT_ERROR_MESSAGE,
+              }),
+            ],
           },
           {
             target: "waitingForPayment",
-            actions: assign(({ event }) => ({
-              orderStatus: event.output.status,
-              errorMessage: null,
-            })),
+            actions: [
+              ({ context, event }) =>
+                behaviorAnalytics.statusPollUpdate(
+                  context.currentOrderId ?? "",
+                  event.output.status,
+                  getCurrentOrderPlan(context),
+                ),
+              assign(({ event }) => ({
+                orderStatus: event.output.status,
+                errorMessage: null,
+              })),
+            ],
           },
         ],
         onError: {
@@ -354,13 +433,17 @@ export const paymentMachine = setup({
     },
     PaymentReturned: {
       target: ".pollingOrder",
-      actions: assign(({ event }) => ({
-        currentOrderId: event.orderId,
-        payParams: null,
-        orderStatus: "pending",
-        orderPollingStartedAt: event.createdAt ?? Date.now(),
-        errorMessage: null,
-      })),
+      actions: [
+        ({ event }) => behaviorAnalytics.statusPollStart(event.orderId),
+        assign(({ event }) => ({
+          currentOrderId: event.orderId,
+          currentOrderPlanId: null,
+          payParams: null,
+          orderStatus: "pending",
+          orderPollingStartedAt: event.createdAt ?? Date.now(),
+          errorMessage: null,
+        })),
+      ],
     },
     PaymentLaunchFailed: {
       target: ".failed",
diff --git a/src/stores/payment/payment-state.ts b/src/stores/payment/payment-state.ts
index 81249220..40876b93 100644
--- a/src/stores/payment/payment-state.ts
+++ b/src/stores/payment/payment-state.ts
@@ -18,6 +18,7 @@ export interface PaymentState {
   autoRenew: boolean;
   agreed: boolean;
   currentOrderId: string | null;
+  currentOrderPlanId: string | null;
   payParams: Record<string, unknown> | null;
   orderStatus: PaymentOrderStatus | null;
   orderPollingStartedAt: number | null;
@@ -34,6 +35,7 @@ export const initialState: PaymentState = {
   autoRenew: true,
   agreed: true,
   currentOrderId: null,
+  currentOrderPlanId: null,
   payParams: null,
   orderStatus: null,
   orderPollingStartedAt: null,