diff --git a/barrelsby.json b/barrelsby.json
index 38c15d5b..2ece9f97 100644
--- a/barrelsby.json
+++ b/barrelsby.json
@@ -14,6 +14,8 @@
     "./src/data/services/api",
     "./src/data/dto/auth",
     "./src/data/dto/chat",
+    "./src/data/dto/feedback",
+    "./src/data/dto/feedback/response",
     "./src/data/dto/metrics",
     "./src/data/dto/user",
     "./src/data/schemas/auth",
@@ -22,6 +24,8 @@
     "./src/data/schemas/chat",
     "./src/data/schemas/chat/request",
     "./src/data/schemas/chat/response",
+    "./src/data/schemas/feedback",
+    "./src/data/schemas/feedback/response",
     "./src/data/schemas/metrics",
     "./src/data/schemas/metrics/request",
     "./src/data/schemas/payment",
diff --git a/docs/backend/FRONTEND_FEEDBACK_API.md b/docs/backend/FRONTEND_FEEDBACK_API.md
new file mode 100644
index 00000000..0b5d4287
--- /dev/null
+++ b/docs/backend/FRONTEND_FEEDBACK_API.md
@@ -0,0 +1,315 @@
+# 问题反馈 API 接口定义
+
+## 1. 文档状态
+
+本文档定义 CozSweet 问题反馈提交接口，供后端实现和前后端联调使用。
+
+前端已经按本文协议完成以下功能：
+
+- 反馈分类和文字提交；
+- 最多 3 张截图；
+- 图片压缩和格式限制；
+- Login Token 与 Guest Token 认证；
+- 提交成功后展示 `feedbackId`。
+
+后端需要实现：
+
+```http
+POST /api/feedback
+```
+
+环境地址：
+
+| 环境 | API Base URL |
+| --- | --- |
+| test 测试环境 | `https://testapi.banlv-ai.com` |
+| pro 预发环境 | `https://proapi.banlv-ai.com` |
+| production 生产环境 | `https://api.banlv-ai.com` |
+
+## 2. 身份认证
+
+接口需要 Bearer Token，支持以下两种身份：
+
+1. 正式用户 Login Token；
+2. 游客 Guest Token。
+
+```http
+Authorization: Bearer <TOKEN>
+```
+
+后端必须从 Token 中解析用户或游客身份，不接受前端传递 `userId`、`guestId` 或其他身份字段。
+
+Token 缺失、无效或过期时返回 HTTP `401`。
+
+## 3. 请求定义
+
+### 3.1 请求地址
+
+```http
+POST <API_BASE_URL>/api/feedback
+```
+
+### 3.2 Content-Type
+
+请求使用：
+
+```http
+Content-Type: multipart/form-data; boundary=<AUTO_GENERATED_BOUNDARY>
+```
+
+调用方不能手工固定 `boundary`。浏览器会根据 FormData 自动生成完整 Content-Type。
+
+### 3.3 Multipart 字段
+
+| 字段 | 类型 | 是否必填 | 说明 |
+| --- | --- | --- | --- |
+| `category` | string | 是 | 反馈分类，只允许标准枚举值。 |
+| `content` | string | 是 | 用户反馈正文，去除首尾空白后长度为 10–2000。 |
+| `context` | string | 是 | JSON 字符串，结构见下文。 |
+| `images` | file[] | 否 | 重复字段，最多 3 张图片。没有图片时不发送该字段。 |
+
+标准 `category`：
+
+| 值 | 含义 |
+| --- | --- |
+| `problem` | 功能异常或使用问题 |
+| `suggestion` | 产品建议 |
+| `payment` | 充值、订阅或支付问题 |
+| `other` | 其他反馈 |
+
+不支持分类别名。非法分类返回 HTTP `400`。
+
+### 3.4 Context JSON
+
+`context` 在 multipart 中是一个 JSON 字符串：
+
+```json
+{
+  "appVersion": "0.1.0",
+  "platform": "android Android 15",
+  "browser": "facebook IAB / Chrome 135.0",
+  "viewport": "392x760@2.75"
+}
+```
+
+| 字段 | 类型 | 最大长度 | 说明 |
+| --- | --- | ---: | --- |
+| `appVersion` | string | 64 | 前端应用版本。 |
+| `platform` | string | 128 | 平台、系统名称和版本。 |
+| `browser` | string | 256 | 浏览器或应用内浏览器信息。 |
+| `viewport` | string | 64 | CSS viewport 宽高和设备像素比。 |
+
+后端只需要保存上述 4 个字段。不要要求前端增加 User-Agent、设备型号、IP、聊天内容、联系方式或 Token。
+
+### 3.5 图片规则
+
+| 规则 | 要求 |
+| --- | --- |
+| 数量 | 0–3 张 |
+| 单文件大小 | 不超过 2 MiB，即 `2 * 1024 * 1024` bytes |
+| 接受格式 | JPEG、PNG、WebP |
+| 接受 MIME | `image/jpeg`、`image/png`、`image/webp` |
+| 推荐请求总大小上限 | 8 MiB |
+
+前端允许用户选择不超过 5 MiB 的源文件，但提交前会压缩到最长边不超过 1600px、目标大小不超过 2 MiB。后端仍需独立执行数量、大小、扩展名、MIME 和文件魔数校验，不能信任浏览器提供的文件名或 Content-Type。
+
+建议后端移除 EXIF 等元数据，并将图片保存到私有存储桶。反馈截图不得使用永久公开 URL。
+
+## 4. 请求示例
+
+### 4.1 仅文字反馈
+
+```bash
+curl -X POST 'https://api.banlv-ai.com/api/feedback' \
+  -H 'Authorization: Bearer <TOKEN>' \
+  -F 'category=problem' \
+  -F 'content=The send button did not respond after I entered a message.' \
+  -F 'context={"appVersion":"0.1.0","platform":"android Android 15","browser":"Chrome 135.0","viewport":"392x760@2.75"}'
+```
+
+### 4.2 带多张截图
+
+```bash
+curl -X POST 'https://api.banlv-ai.com/api/feedback' \
+  -H 'Authorization: Bearer <TOKEN>' \
+  -F 'category=payment' \
+  -F 'content=The payment completed but my balance did not update.' \
+  -F 'context={"appVersion":"0.1.0","platform":"android Android 15","browser":"facebook IAB / Chrome 135.0","viewport":"392x760@2.75"}' \
+  -F 'images=@payment-screen-1.webp;type=image/webp' \
+  -F 'images=@payment-screen-2.jpg;type=image/jpeg'
+```
+
+## 5. 成功响应
+
+成功时返回 HTTP `200`：
+
+```json
+{
+  "success": true,
+  "message": "Feedback submitted",
+  "data": {
+    "feedbackId": "c5db8e32-60f0-4f47-81bb-c22254c0562f"
+  }
+}
+```
+
+前端公开响应字段只有：
+
+| 字段 | 类型 | 是否必填 | 说明 |
+| --- | --- | --- | --- |
+| `data.feedbackId` | string | 是 | 非空反馈编号，推荐使用 UUID。 |
+
+前端不需要后端返回用户信息、反馈正文、图片地址、状态、创建时间或诊断上下文。
+
+## 6. 失败响应
+
+失败响应使用统一 envelope：
+
+```json
+{
+  "success": false,
+  "message": "Feedback content must contain at least 10 characters",
+  "error": "INVALID_FEEDBACK_CONTENT"
+}
+```
+
+建议状态码：
+
+| HTTP 状态 | error | 场景 |
+| ---: | --- | --- |
+| `400` | `INVALID_FEEDBACK_CATEGORY` | 分类不在标准枚举中。 |
+| `400` | `INVALID_FEEDBACK_CONTENT` | 正文为空或长度不在 10–2000。 |
+| `400` | `INVALID_FEEDBACK_CONTEXT` | Context 不是合法 JSON 或字段不合法。 |
+| `400` | `TOO_MANY_FEEDBACK_IMAGES` | 图片超过 3 张。 |
+| `401` | `UNAUTHORIZED` | Token 缺失、无效或过期。 |
+| `413` | `FEEDBACK_PAYLOAD_TOO_LARGE` | 单文件或请求总大小超过限制。 |
+| `415` | `UNSUPPORTED_FEEDBACK_IMAGE` | 图片格式、MIME 或文件魔数不支持。 |
+| `429` | `FEEDBACK_RATE_LIMITED` | 用户或游客提交过于频繁。 |
+| `500` | `FEEDBACK_SUBMIT_FAILED` | 持久化或文件存储失败。 |
+
+`message` 应当是可展示给用户的简短英文文本。不得在响应中返回堆栈、存储路径、数据库错误或内部实现信息。
+
+## 7. 后端处理流程
+
+推荐处理顺序：
+
+1. 验证 Bearer Token，解析正式用户或游客身份。
+2. 读取 multipart 字段并验证分类、正文和 Context。
+3. 在读取完整文件前检查图片数量和请求大小。
+4. 校验每张图片的真实格式、文件魔数、尺寸和大小。
+5. 使用服务端生成的随机对象名写入私有存储。
+6. 创建反馈记录并关联图片对象。
+7. 返回非空 `feedbackId`。
+8. 任一步失败时清理本次已经上传但未关联的图片。
+
+每个成功请求创建一条反馈记录。当前前端没有发送 Idempotency-Key，因此后端不能依赖客户端幂等键去重。
+
+## 8. 推荐数据模型
+
+反馈主记录最少需要：
+
+| 字段 | 说明 |
+| --- | --- |
+| `id` | UUID，作为 `feedbackId` 返回。 |
+| `user_id` | 正式用户 ID，可为空。 |
+| `guest_id` | Guest 身份 ID，可为空。 |
+| `category` | 标准反馈分类。 |
+| `content` | 反馈正文。 |
+| `context` | JSON/JSONB，只保存定义的 4 个字段。 |
+| `status` | 内部处理状态，例如 `open`、`resolved`。不返回前端。 |
+| `created_at` | 服务端创建时间。 |
+
+图片记录最少需要反馈 ID、私有对象 key、MIME、字节大小、宽高和创建时间。不要把用户原始文件名作为存储对象名。
+
+正式用户必须只写入 `user_id`，Guest 必须只写入 `guest_id`。身份信息由 Token 派生。
+
+## 9. 安全与日志
+
+- 建议按用户或 Guest 身份限流，例如每小时不超过 10 次。
+- 普通应用日志不得记录反馈正文、Token、图片内容、原始文件名或完整 Context。
+- 可以记录 `feedbackId`、分类、图片数量、处理时长和错误码。
+- 图片下载和后台查看必须经过授权，不允许匿名公开访问。
+- 数据保留、删除和后台访问需要遵循现有隐私政策。
+
+## 10. OpenAPI 参考
+
+```yaml
+paths:
+  /api/feedback:
+    post:
+      summary: Submit user feedback
+      security:
+        - bearerAuth: []
+      requestBody:
+        required: true
+        content:
+          multipart/form-data:
+            schema:
+              type: object
+              required:
+                - category
+                - content
+                - context
+              properties:
+                category:
+                  type: string
+                  enum: [problem, suggestion, payment, other]
+                content:
+                  type: string
+                  minLength: 10
+                  maxLength: 2000
+                context:
+                  type: string
+                  description: JSON-encoded FeedbackContext
+                images:
+                  type: array
+                  maxItems: 3
+                  items:
+                    type: string
+                    format: binary
+      responses:
+        "200":
+          description: Feedback submitted
+          content:
+            application/json:
+              schema:
+                type: object
+                required: [success, data]
+                properties:
+                  success:
+                    type: boolean
+                    const: true
+                  message:
+                    type: string
+                  data:
+                    type: object
+                    required: [feedbackId]
+                    properties:
+                      feedbackId:
+                        type: string
+                        minLength: 1
+        "400":
+          description: Invalid feedback payload
+        "401":
+          description: Missing or invalid token
+        "413":
+          description: Payload too large
+        "415":
+          description: Unsupported image
+        "429":
+          description: Too many requests
+        "500":
+          description: Feedback persistence failed
+```
+
+## 11. 联调验收
+
+后端完成后至少验证：
+
+1. Login Token 和 Guest Token 都能成功提交。
+2. 无图片、1 张图片和 3 张图片均能创建反馈。
+3. 第 4 张图片、超大图片、伪造 MIME 和非法 Context 被拒绝。
+4. 成功响应始终包含非空 `data.feedbackId`。
+5. 存储失败时不留下孤立图片对象或半成品反馈记录。
+6. 日志中不出现反馈正文、Token、图片内容和原始文件名。
+7. 同一身份超过限流阈值后返回 HTTP `429`。
diff --git a/src/app/feedback/__tests__/feedback-image.test.tsx b/src/app/feedback/__tests__/feedback-image.test.tsx
new file mode 100644
index 00000000..db59aad2
--- /dev/null
+++ b/src/app/feedback/__tests__/feedback-image.test.tsx
@@ -0,0 +1,76 @@
+import { afterEach, describe, expect, it, vi } from "vitest";
+
+import {
+  FEEDBACK_IMAGE_SOURCE_MAX_BYTES,
+  fitWithinDimension,
+  prepareFeedbackImage,
+  validateFeedbackImage,
+} from "../feedback-image";
+
+describe("feedback image preparation", () => {
+  afterEach(() => {
+    vi.unstubAllGlobals();
+    vi.restoreAllMocks();
+  });
+
+  it("accepts supported formats and rejects unsupported or oversized files", () => {
+    expect(
+      validateFeedbackImage({ type: "image/png", size: 100 } as File),
+    ).toBeNull();
+    expect(
+      validateFeedbackImage({ type: "image/gif", size: 100 } as File),
+    ).toBe("Please choose a JPEG, PNG, or WebP image.");
+    expect(
+      validateFeedbackImage({
+        type: "image/jpeg",
+        size: FEEDBACK_IMAGE_SOURCE_MAX_BYTES + 1,
+      } as File),
+    ).toBe("Each image must be 5 MB or smaller.");
+  });
+
+  it("fits images within the maximum dimension without stretching", () => {
+    expect(fitWithinDimension(3200, 1600, 1600)).toEqual({
+      width: 1600,
+      height: 800,
+    });
+    expect(fitWithinDimension(640, 480, 1600)).toEqual({
+      width: 640,
+      height: 480,
+    });
+  });
+
+  it("resizes and compresses large screenshots", async () => {
+    const close = vi.fn();
+    vi.stubGlobal(
+      "createImageBitmap",
+      vi.fn(async () => ({ width: 3200, height: 1600, close })),
+    );
+    const drawImage = vi.fn();
+    vi.spyOn(HTMLCanvasElement.prototype, "getContext").mockReturnValue({
+      drawImage,
+    } as unknown as CanvasRenderingContext2D);
+    vi.spyOn(HTMLCanvasElement.prototype, "toBlob").mockImplementation(
+      (callback, type) => {
+        callback(new Blob(["compressed"], { type: type ?? "image/webp" }));
+      },
+    );
+    const file = new File(
+      [new Uint8Array(FEEDBACK_IMAGE_SOURCE_MAX_BYTES - 1)],
+      "screen.png",
+      { type: "image/png" },
+    );
+
+    const result = await prepareFeedbackImage(file);
+
+    expect(result.name).toBe("screen.webp");
+    expect(result.type).toBe("image/webp");
+    expect(drawImage).toHaveBeenCalledWith(
+      expect.anything(),
+      0,
+      0,
+      1600,
+      800,
+    );
+    expect(close).toHaveBeenCalledTimes(1);
+  });
+});
diff --git a/src/app/feedback/__tests__/feedback-screen.test.tsx b/src/app/feedback/__tests__/feedback-screen.test.tsx
new file mode 100644
index 00000000..f65226b1
--- /dev/null
+++ b/src/app/feedback/__tests__/feedback-screen.test.tsx
@@ -0,0 +1,106 @@
+import { act } from "react";
+import { createRoot, type Root } from "react-dom/client";
+import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
+
+import { Result } from "@/utils/result";
+
+import { FeedbackScreen } from "../feedback-screen";
+
+const mocks = vi.hoisted(() => ({
+  replace: vi.fn(),
+  submitFeedback: vi.fn(),
+}));
+
+vi.mock("@/router/use-app-navigator", () => ({
+  useAppNavigator: () => ({ replace: mocks.replace }),
+}));
+
+vi.mock("@/lib/feedback", () => ({
+  submitFeedback: mocks.submitFeedback,
+}));
+
+vi.mock("../feedback-context", () => ({
+  createFeedbackContext: () => ({
+    appVersion: "test",
+    platform: "android",
+    browser: "chrome",
+    viewport: "390x844@3",
+  }),
+}));
+
+describe("FeedbackScreen", () => {
+  let container: HTMLDivElement;
+  let root: Root;
+
+  beforeEach(() => {
+    (globalThis as { IS_REACT_ACT_ENVIRONMENT?: boolean })
+      .IS_REACT_ACT_ENVIRONMENT = true;
+    mocks.replace.mockReset();
+    mocks.submitFeedback.mockReset();
+    container = document.createElement("div");
+    document.body.appendChild(container);
+    root = createRoot(container);
+  });
+
+  afterEach(() => {
+    act(() => root.unmount());
+    container.remove();
+  });
+
+  it("renders all categories and defaults to Problem", () => {
+    act(() => root.render(<FeedbackScreen />));
+
+    expect(container.textContent).toContain("Help us improve CozSweet");
+    expect(container.textContent).toContain("Problem");
+    expect(container.textContent).toContain("Suggestion");
+    expect(container.textContent).toContain("Payment");
+    expect(container.textContent).toContain("Other");
+    expect(
+      container.querySelector<HTMLInputElement>('input[value="problem"]')
+        ?.checked,
+    ).toBe(true);
+  });
+
+  it("submits valid text and renders the feedback id", async () => {
+    mocks.submitFeedback.mockResolvedValue(
+      Result.ok({ feedbackId: "feedback-123" }),
+    );
+    act(() => root.render(<FeedbackScreen />));
+    const textarea = container.querySelector("textarea");
+    if (!textarea) throw new Error("Expected feedback textarea");
+
+    act(() => setTextareaValue(textarea, "The message button stopped working."));
+    const submit = container.querySelector<HTMLButtonElement>(
+      'button[type="submit"]',
+    );
+    expect(submit?.disabled).toBe(false);
+
+    await act(async () => {
+      submit?.click();
+      await Promise.resolve();
+    });
+
+    expect(mocks.submitFeedback).toHaveBeenCalledWith({
+      category: "problem",
+      content: "The message button stopped working.",
+      context: {
+        appVersion: "test",
+        platform: "android",
+        browser: "chrome",
+        viewport: "390x844@3",
+      },
+      images: [],
+    });
+    expect(container.textContent).toContain("feedback-123");
+    expect(container.textContent).toContain("Thank you for helping us.");
+  });
+});
+
+function setTextareaValue(element: HTMLTextAreaElement, value: string): void {
+  const setter = Object.getOwnPropertyDescriptor(
+    HTMLTextAreaElement.prototype,
+    "value",
+  )?.set;
+  setter?.call(element, value);
+  element.dispatchEvent(new Event("input", { bubbles: true }));
+}
diff --git a/src/app/feedback/feedback-context.ts b/src/app/feedback/feedback-context.ts
new file mode 100644
index 00000000..041561f0
--- /dev/null
+++ b/src/app/feedback/feedback-context.ts
@@ -0,0 +1,31 @@
+import packageInfo from "../../../package.json";
+
+import type { FeedbackContext } from "@/data/dto/feedback";
+import { BrowserDetector } from "@/utils/browser-detect";
+import { PlatformDetector } from "@/utils/platform-detect";
+
+export function createFeedbackContext(): FeedbackContext {
+  const platform = PlatformDetector.getPlatformInfo();
+  const browser = BrowserDetector.getBrowserInfo();
+  const browserName = browser.inAppBrowserName
+    ? `${browser.inAppBrowserName} IAB / ${browser.name}`
+    : browser.name;
+
+  return {
+    appVersion: packageInfo.version,
+    platform: joinContextParts([
+      platform.platform,
+      platform.osName,
+      platform.osVersion,
+    ]),
+    browser: joinContextParts([browserName, browser.version]),
+    viewport:
+      typeof window === "undefined"
+        ? "unknown"
+        : `${window.innerWidth}x${window.innerHeight}@${window.devicePixelRatio}`,
+  };
+}
+
+function joinContextParts(parts: readonly string[]): string {
+  return parts.filter((part) => part.trim().length > 0).join(" ") || "unknown";
+}
diff --git a/src/app/feedback/feedback-image.ts b/src/app/feedback/feedback-image.ts
new file mode 100644
index 00000000..f2deb981
--- /dev/null
+++ b/src/app/feedback/feedback-image.ts
@@ -0,0 +1,159 @@
+const SUPPORTED_IMAGE_TYPES = new Set([
+  "image/jpeg",
+  "image/png",
+  "image/webp",
+]);
+
+export const FEEDBACK_IMAGE_ACCEPT = "image/jpeg,image/png,image/webp";
+export const FEEDBACK_IMAGE_LIMIT = 3;
+export const FEEDBACK_IMAGE_SOURCE_MAX_BYTES = 5 * 1024 * 1024;
+export const FEEDBACK_IMAGE_TARGET_MAX_BYTES = 2 * 1024 * 1024;
+export const FEEDBACK_IMAGE_MAX_DIMENSION = 1600;
+
+const OUTPUT_QUALITIES = [0.86, 0.74, 0.62, 0.5] as const;
+const DIMENSION_CAPS = [1600, 1400, 1200, 1000, 800] as const;
+
+interface DecodedImage {
+  width: number;
+  height: number;
+  source: CanvasImageSource;
+  dispose: () => void;
+}
+
+export function validateFeedbackImage(file: File): string | null {
+  if (!SUPPORTED_IMAGE_TYPES.has(file.type)) {
+    return "Please choose a JPEG, PNG, or WebP image.";
+  }
+  if (file.size > FEEDBACK_IMAGE_SOURCE_MAX_BYTES) {
+    return "Each image must be 5 MB or smaller.";
+  }
+  return null;
+}
+
+export async function prepareFeedbackImage(file: File): Promise<File> {
+  const validationError = validateFeedbackImage(file);
+  if (validationError) throw new Error(validationError);
+
+  const decoded = await decodeImage(file);
+  try {
+    const longestEdge = Math.max(decoded.width, decoded.height);
+    if (
+      longestEdge <= FEEDBACK_IMAGE_MAX_DIMENSION &&
+      file.size <= FEEDBACK_IMAGE_TARGET_MAX_BYTES
+    ) {
+      return file;
+    }
+
+    const mimeType = file.type === "image/jpeg" ? "image/jpeg" : "image/webp";
+    let smallestBlob: Blob | null = null;
+    const renderedSizes = new Set<string>();
+
+    for (const dimensionCap of DIMENSION_CAPS) {
+      const size = fitWithinDimension(
+        decoded.width,
+        decoded.height,
+        dimensionCap,
+      );
+      const sizeKey = `${size.width}x${size.height}`;
+      if (renderedSizes.has(sizeKey)) continue;
+      renderedSizes.add(sizeKey);
+
+      const canvas = document.createElement("canvas");
+      canvas.width = size.width;
+      canvas.height = size.height;
+      const context = canvas.getContext("2d");
+      if (!context) throw new Error("This browser cannot process images.");
+      context.drawImage(decoded.source, 0, 0, size.width, size.height);
+
+      for (const quality of OUTPUT_QUALITIES) {
+        const blob = await canvasToBlob(canvas, mimeType, quality);
+        if (!smallestBlob || blob.size < smallestBlob.size) smallestBlob = blob;
+        if (blob.size <= FEEDBACK_IMAGE_TARGET_MAX_BYTES) {
+          return toFeedbackFile(blob, file.name);
+        }
+      }
+    }
+
+    if (smallestBlob && smallestBlob.size <= FEEDBACK_IMAGE_TARGET_MAX_BYTES) {
+      return toFeedbackFile(smallestBlob, file.name);
+    }
+    throw new Error("This image is still too large after compression.");
+  } finally {
+    decoded.dispose();
+  }
+}
+
+export function fitWithinDimension(
+  width: number,
+  height: number,
+  maxDimension: number,
+): { width: number; height: number } {
+  const scale = Math.min(1, maxDimension / Math.max(width, height));
+  return {
+    width: Math.max(1, Math.round(width * scale)),
+    height: Math.max(1, Math.round(height * scale)),
+  };
+}
+
+async function decodeImage(file: File): Promise<DecodedImage> {
+  if (typeof createImageBitmap === "function") {
+    try {
+      const bitmap = await createImageBitmap(file, {
+        imageOrientation: "from-image",
+      });
+      return {
+        width: bitmap.width,
+        height: bitmap.height,
+        source: bitmap,
+        dispose: () => bitmap.close(),
+      };
+    } catch {
+      // Some WebViews expose createImageBitmap but cannot decode every format.
+    }
+  }
+
+  const objectUrl = URL.createObjectURL(file);
+  try {
+    const image = await new Promise<HTMLImageElement>((resolve, reject) => {
+      const element = new Image();
+      element.onload = () => resolve(element);
+      element.onerror = () => reject(new Error("This image could not be read."));
+      element.src = objectUrl;
+    });
+    return {
+      width: image.naturalWidth,
+      height: image.naturalHeight,
+      source: image,
+      dispose: () => URL.revokeObjectURL(objectUrl),
+    };
+  } catch (error) {
+    URL.revokeObjectURL(objectUrl);
+    throw error;
+  }
+}
+
+function canvasToBlob(
+  canvas: HTMLCanvasElement,
+  mimeType: string,
+  quality: number,
+): Promise<Blob> {
+  return new Promise((resolve, reject) => {
+    canvas.toBlob(
+      (blob) => {
+        if (blob) resolve(blob);
+        else reject(new Error("This image could not be compressed."));
+      },
+      mimeType,
+      quality,
+    );
+  });
+}
+
+function toFeedbackFile(blob: Blob, originalName: string): File {
+  const extension = blob.type === "image/jpeg" ? "jpg" : "webp";
+  const baseName = originalName.replace(/\.[^.]+$/, "") || "feedback-image";
+  return new File([blob], `${baseName}.${extension}`, {
+    type: blob.type,
+    lastModified: Date.now(),
+  });
+}
diff --git a/src/app/feedback/feedback-screen.module.css b/src/app/feedback/feedback-screen.module.css
new file mode 100644
index 00000000..6a125146
--- /dev/null
+++ b/src/app/feedback/feedback-screen.module.css
@@ -0,0 +1,500 @@
+.shell,
+.successShell {
+  position: relative;
+  min-height: var(--app-viewport-height, 100dvh);
+  box-sizing: border-box;
+  overflow: hidden;
+  color: #21191c;
+  background:
+    radial-gradient(circle at 88% 4%, rgba(246, 87, 160, 0.14), transparent 28%),
+    radial-gradient(circle at 4% 66%, rgba(219, 181, 137, 0.13), transparent 30%),
+    linear-gradient(180deg, #f8f6f4 0%, #fffafa 48%, #ffffff 100%);
+}
+
+.shell {
+  padding:
+    calc(var(--app-safe-top, 0px) + 18px)
+    calc(var(--app-safe-right, 0px) + clamp(18px, 5vw, 28px))
+    calc(var(--app-safe-bottom, 0px) + 28px)
+    calc(var(--app-safe-left, 0px) + clamp(18px, 5vw, 28px));
+}
+
+.glowOne,
+.glowTwo,
+.successGlow {
+  position: absolute;
+  pointer-events: none;
+  border-radius: 999px;
+  filter: blur(3px);
+}
+
+.glowOne {
+  top: -74px;
+  right: -88px;
+  width: 210px;
+  height: 210px;
+  background: rgba(246, 87, 160, 0.09);
+}
+
+.glowTwo {
+  bottom: 12%;
+  left: -110px;
+  width: 220px;
+  height: 220px;
+  background: rgba(208, 164, 112, 0.08);
+}
+
+.header,
+.form {
+  position: relative;
+  z-index: 1;
+}
+
+.header {
+  display: grid;
+  grid-template-columns: auto minmax(0, 1fr);
+  align-items: start;
+  gap: 14px;
+  margin: 4px 0 22px;
+}
+
+.headingBlock {
+  min-width: 0;
+  padding-top: 2px;
+}
+
+.eyebrow {
+  margin: 0 0 6px;
+  color: #d74382;
+  font-size: 11px;
+  font-weight: 850;
+  letter-spacing: 0.13em;
+  text-transform: uppercase;
+}
+
+.title,
+.successTitle {
+  margin: 0;
+  color: #21191c;
+  font-family: Georgia, "Times New Roman", serif;
+  font-size: clamp(27px, 7vw, 36px);
+  font-weight: 650;
+  line-height: 1.08;
+  letter-spacing: -0.025em;
+}
+
+.subtitle {
+  max-width: 390px;
+  margin: 10px 0 0;
+  color: #75666c;
+  font-size: 14px;
+  font-weight: 560;
+  line-height: 1.5;
+}
+
+.form {
+  display: flex;
+  flex-direction: column;
+  gap: 19px;
+  padding: clamp(18px, 4.8vw, 24px);
+  border: 1px solid rgba(45, 31, 36, 0.065);
+  border-radius: 28px;
+  background: rgba(255, 255, 255, 0.88);
+  box-shadow: 0 20px 52px rgba(70, 48, 55, 0.09);
+  backdrop-filter: blur(18px);
+}
+
+.fieldset,
+.fieldGroup {
+  min-width: 0;
+  margin: 0;
+  padding: 0;
+  border: 0;
+}
+
+.fieldGroup {
+  display: flex;
+  flex-direction: column;
+  gap: 9px;
+}
+
+.fieldLabel {
+  margin: 0 0 10px;
+  color: #32272b;
+  font-size: 14px;
+  font-weight: 790;
+  line-height: 1.25;
+}
+
+h2.fieldLabel {
+  margin-bottom: 3px;
+}
+
+.fieldLabel span {
+  margin-left: 4px;
+  color: #9a8b90;
+  font-size: 11px;
+  font-weight: 680;
+  text-transform: uppercase;
+}
+
+.categoryGrid {
+  display: grid;
+  grid-template-columns: repeat(2, minmax(0, 1fr));
+  gap: 9px;
+}
+
+.categoryCard {
+  position: relative;
+  display: flex;
+  min-height: 46px;
+  align-items: center;
+  gap: 8px;
+  box-sizing: border-box;
+  padding: 10px 12px;
+  border: 1px solid #ebe3e5;
+  border-radius: 16px;
+  background: #fbf9f8;
+  color: #74666b;
+  cursor: pointer;
+  font-size: 13px;
+  font-weight: 720;
+  transition: border-color 0.16s ease, background 0.16s ease, color 0.16s ease, transform 0.16s ease;
+}
+
+.categoryCard:hover {
+  border-color: rgba(246, 87, 160, 0.28);
+  transform: translateY(-1px);
+}
+
+.categoryCard:has(input:focus-visible) {
+  outline: 2px solid #f657a0;
+  outline-offset: 2px;
+}
+
+.categoryCardSelected {
+  border-color: rgba(246, 87, 160, 0.62);
+  background: linear-gradient(135deg, #fff6fa, #fffaf7);
+  color: #d74382;
+  box-shadow: 0 7px 18px rgba(246, 87, 160, 0.1);
+}
+
+.categoryCheck {
+  margin-left: auto;
+}
+
+.textareaFrame {
+  position: relative;
+}
+
+.textarea {
+  display: block;
+  width: 100%;
+  min-height: 142px;
+  resize: vertical;
+  box-sizing: border-box;
+  padding: 14px 14px 36px;
+  border: 1px solid #e9e0e3;
+  border-radius: 19px;
+  outline: none;
+  background: #fbf9f8;
+  color: #2f2529;
+  font: inherit;
+  font-size: 15px;
+  line-height: 1.52;
+  transition: border-color 0.16s ease, background 0.16s ease, box-shadow 0.16s ease;
+}
+
+.textarea::placeholder {
+  color: #aaa0a3;
+}
+
+.textarea:focus {
+  border-color: rgba(246, 87, 160, 0.62);
+  background: #ffffff;
+  box-shadow: 0 0 0 4px rgba(246, 87, 160, 0.08);
+}
+
+.characterCount {
+  position: absolute;
+  right: 13px;
+  bottom: 11px;
+  color: #9b8d92;
+  font-size: 11px;
+  font-weight: 680;
+}
+
+.imageHeading {
+  display: flex;
+  align-items: end;
+  justify-content: space-between;
+  gap: 12px;
+}
+
+.fieldHint {
+  margin: 0;
+  color: #998b90;
+  font-size: 11px;
+  font-weight: 570;
+}
+
+.imageCount {
+  flex: 0 0 auto;
+  color: #8d7c82;
+  font-size: 12px;
+  font-weight: 760;
+}
+
+.imageGrid {
+  display: grid;
+  grid-template-columns: repeat(3, minmax(0, 1fr));
+  gap: 9px;
+}
+
+.imagePreview,
+.addImageButton {
+  position: relative;
+  aspect-ratio: 1;
+  overflow: hidden;
+  border-radius: 17px;
+}
+
+.imagePreview {
+  background: #eee8e9;
+  box-shadow: inset 0 0 0 1px rgba(50, 35, 41, 0.06);
+}
+
+.previewImage {
+  object-fit: cover;
+}
+
+.removeImageButton {
+  position: absolute;
+  top: 6px;
+  right: 6px;
+  display: inline-flex;
+  width: 28px;
+  height: 28px;
+  align-items: center;
+  justify-content: center;
+  padding: 0;
+  border: 1px solid rgba(255, 255, 255, 0.32);
+  border-radius: 999px;
+  background: rgba(28, 21, 24, 0.72);
+  color: #ffffff;
+  cursor: pointer;
+  backdrop-filter: blur(8px);
+}
+
+.removeImageButton:focus-visible,
+.addImageButton:has(input:focus-visible) {
+  outline: 2px solid #f657a0;
+  outline-offset: 2px;
+}
+
+.addImageButton {
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  flex-direction: column;
+  gap: 6px;
+  box-sizing: border-box;
+  border: 1px dashed rgba(215, 67, 130, 0.35);
+  background: linear-gradient(145deg, #fff8fb, #faf7f5);
+  color: #d74382;
+  cursor: pointer;
+  font-size: 11px;
+  font-weight: 760;
+  transition: border-color 0.16s ease, background 0.16s ease, transform 0.16s ease;
+}
+
+.addImageButton:hover {
+  border-color: rgba(215, 67, 130, 0.68);
+  background: #fff4f9;
+  transform: translateY(-1px);
+}
+
+.addImageButtonBusy {
+  cursor: wait;
+  opacity: 0.68;
+}
+
+.statusSlot {
+  min-height: 18px;
+  margin: -5px 0 -7px;
+}
+
+.errorMessage {
+  margin: 0;
+  color: #c43e55;
+  font-size: 12px;
+  font-weight: 650;
+  line-height: 1.4;
+}
+
+.primaryButton {
+  display: inline-flex;
+  width: 100%;
+  min-height: 52px;
+  align-items: center;
+  justify-content: center;
+  gap: 9px;
+  box-sizing: border-box;
+  padding: 12px 22px;
+  border: 0;
+  border-radius: 999px;
+  background: linear-gradient(100deg, #f84d96 0%, #ff6ea8 55%, #f28b72 120%);
+  color: #ffffff;
+  cursor: pointer;
+  font: inherit;
+  font-size: 15px;
+  font-weight: 820;
+  box-shadow: 0 13px 28px rgba(248, 77, 150, 0.27);
+  transition: filter 0.16s ease, box-shadow 0.16s ease, transform 0.16s ease;
+}
+
+.primaryButton:hover:not(:disabled) {
+  filter: brightness(1.03);
+  box-shadow: 0 16px 32px rgba(248, 77, 150, 0.34);
+  transform: translateY(-1px);
+}
+
+.primaryButton:active:not(:disabled) {
+  transform: translateY(1px) scale(0.99);
+}
+
+.primaryButton:focus-visible {
+  outline: 2px solid #f657a0;
+  outline-offset: 3px;
+}
+
+.primaryButton:disabled {
+  cursor: not-allowed;
+  opacity: 0.52;
+  box-shadow: none;
+}
+
+.visuallyHidden {
+  position: absolute;
+  width: 1px;
+  height: 1px;
+  overflow: hidden;
+  clip: rect(0 0 0 0);
+  clip-path: inset(50%);
+  white-space: nowrap;
+}
+
+.successShell {
+  display: grid;
+  place-items: center;
+  padding:
+    calc(var(--app-safe-top, 0px) + 28px)
+    calc(var(--app-safe-right, 0px) + 24px)
+    calc(var(--app-safe-bottom, 0px) + 28px)
+    calc(var(--app-safe-left, 0px) + 24px);
+}
+
+.successGlow {
+  width: 330px;
+  height: 330px;
+  background: rgba(246, 87, 160, 0.12);
+  filter: blur(12px);
+}
+
+.successCard {
+  position: relative;
+  z-index: 1;
+  width: 100%;
+  max-width: 420px;
+  box-sizing: border-box;
+  padding: clamp(28px, 8vw, 42px) clamp(22px, 7vw, 36px);
+  border: 1px solid rgba(45, 31, 36, 0.07);
+  border-radius: 30px;
+  background: rgba(255, 255, 255, 0.92);
+  text-align: center;
+  box-shadow: 0 26px 70px rgba(70, 48, 55, 0.12);
+  backdrop-filter: blur(20px);
+}
+
+.successIcon {
+  display: inline-flex;
+  width: 72px;
+  height: 72px;
+  align-items: center;
+  justify-content: center;
+  margin-bottom: 20px;
+  border-radius: 24px;
+  background: linear-gradient(145deg, #fff0f7, #fff8f1);
+  color: #e34d8b;
+  box-shadow: 0 12px 28px rgba(246, 87, 160, 0.14);
+}
+
+.successCopy {
+  margin: 14px auto 24px;
+  color: #76666c;
+  font-size: 14px;
+  line-height: 1.55;
+}
+
+.feedbackIdBlock {
+  display: flex;
+  flex-direction: column;
+  gap: 5px;
+  margin-bottom: 24px;
+  padding: 13px 16px;
+  border-radius: 16px;
+  background: #faf6f7;
+  color: #8f7f85;
+  font-size: 10px;
+  font-weight: 780;
+  letter-spacing: 0.08em;
+  text-transform: uppercase;
+}
+
+.feedbackIdBlock strong {
+  overflow-wrap: anywhere;
+  color: #45373c;
+  font-size: 13px;
+  letter-spacing: 0.03em;
+  text-transform: none;
+}
+
+@media (max-width: 350px) {
+  .shell {
+    padding-right: calc(var(--app-safe-right, 0px) + 14px);
+    padding-left: calc(var(--app-safe-left, 0px) + 14px);
+  }
+
+  .form {
+    padding: 16px;
+    border-radius: 24px;
+  }
+
+  .categoryGrid {
+    grid-template-columns: 1fr;
+  }
+}
+
+@media (prefers-reduced-motion: no-preference) {
+  .headingBlock,
+  .form,
+  .successCard {
+    animation: reveal 0.38s ease both;
+  }
+
+  .form {
+    animation-delay: 60ms;
+  }
+}
+
+@keyframes reveal {
+  from {
+    opacity: 0;
+    transform: translateY(9px);
+  }
+
+  to {
+    opacity: 1;
+    transform: translateY(0);
+  }
+}
diff --git a/src/app/feedback/feedback-screen.tsx b/src/app/feedback/feedback-screen.tsx
new file mode 100644
index 00000000..d74f089a
--- /dev/null
+++ b/src/app/feedback/feedback-screen.tsx
@@ -0,0 +1,239 @@
+"use client";
+
+import type { ChangeEvent, ComponentType } from "react";
+import Image from "next/image";
+import {
+  Bug,
+  Check,
+  CheckCircle2,
+  CreditCard,
+  ImagePlus,
+  Lightbulb,
+  MessageCircleMore,
+  Send,
+  Trash2,
+} from "lucide-react";
+
+import { BackButton } from "@/app/_components";
+import { MobileShell } from "@/app/_components/core";
+import type { FeedbackCategory } from "@/data/dto/feedback";
+import { ROUTES } from "@/router/routes";
+import { useAppNavigator } from "@/router/use-app-navigator";
+
+import {
+  FEEDBACK_IMAGE_ACCEPT,
+  FEEDBACK_IMAGE_LIMIT,
+} from "./feedback-image";
+import {
+  FEEDBACK_CONTENT_MAX_LENGTH,
+  useFeedbackSubmission,
+} from "./use-feedback-submission";
+
+import styles from "./feedback-screen.module.css";
+
+interface CategoryOption {
+  value: FeedbackCategory;
+  label: string;
+  icon: ComponentType<{ size?: number; strokeWidth?: number }>;
+}
+
+const CATEGORY_OPTIONS: readonly CategoryOption[] = [
+  { value: "problem", label: "Problem", icon: Bug },
+  { value: "suggestion", label: "Suggestion", icon: Lightbulb },
+  { value: "payment", label: "Payment", icon: CreditCard },
+  { value: "other", label: "Other", icon: MessageCircleMore },
+];
+
+export function FeedbackScreen() {
+  const navigator = useAppNavigator();
+  const form = useFeedbackSubmission();
+
+  if (form.feedbackId) {
+    return (
+      <MobileShell background="#f8f6f4">
+        <main className={styles.successShell}>
+          <div className={styles.successGlow} aria-hidden="true" />
+          <section className={styles.successCard} aria-live="polite">
+            <span className={styles.successIcon} aria-hidden="true">
+              <CheckCircle2 size={36} strokeWidth={1.9} />
+            </span>
+            <p className={styles.eyebrow}>Feedback received</p>
+            <h1 className={styles.successTitle}>Thank you for helping us.</h1>
+            <p className={styles.successCopy}>
+              Your report is safely on its way to the CozSweet team.
+            </p>
+            <div className={styles.feedbackIdBlock}>
+              <span>Feedback ID</span>
+              <strong>{form.feedbackId}</strong>
+            </div>
+            <button
+              type="button"
+              data-analytics-key="feedback.back_to_chat"
+              className={styles.primaryButton}
+              onClick={() => navigator.replace(ROUTES.chat)}
+            >
+              Back to Chat
+            </button>
+          </section>
+        </main>
+      </MobileShell>
+    );
+  }
+
+  const handleImageChange = (event: ChangeEvent<HTMLInputElement>) => {
+    if (event.target.files) void form.addImages(event.target.files);
+    event.target.value = "";
+  };
+
+  return (
+    <MobileShell background="#f8f6f4">
+      <main className={styles.shell}>
+        <div className={styles.glowOne} aria-hidden="true" />
+        <div className={styles.glowTwo} aria-hidden="true" />
+
+        <header className={styles.header}>
+          <BackButton
+            href={ROUTES.chat}
+            variant="soft"
+            ariaLabel="Back to chat"
+            analyticsKey="feedback.back_to_chat"
+          />
+          <div className={styles.headingBlock}>
+            <p className={styles.eyebrow}>Support</p>
+            <h1 className={styles.title}>Help us improve CozSweet</h1>
+            <p className={styles.subtitle}>
+              Tell us what happened. Screenshots help us understand it faster.
+            </p>
+          </div>
+        </header>
+
+        <form className={styles.form} onSubmit={form.submit} noValidate>
+          <fieldset className={styles.fieldset}>
+            <legend className={styles.fieldLabel}>What is this about?</legend>
+            <div className={styles.categoryGrid}>
+              {CATEGORY_OPTIONS.map((option) => {
+                const Icon = option.icon;
+                const selected = form.category === option.value;
+                return (
+                  <label
+                    key={option.value}
+                    className={`${styles.categoryCard} ${selected ? styles.categoryCardSelected : ""}`}
+                  >
+                    <input
+                      type="radio"
+                      name="feedback-category"
+                      value={option.value}
+                      checked={selected}
+                      disabled={form.isSubmitting}
+                      className={styles.visuallyHidden}
+                      onChange={() => form.setCategory(option.value)}
+                    />
+                    <Icon size={18} strokeWidth={2} />
+                    <span>{option.label}</span>
+                    {selected ? (
+                      <Check className={styles.categoryCheck} size={14} />
+                    ) : null}
+                  </label>
+                );
+              })}
+            </div>
+          </fieldset>
+
+          <div className={styles.fieldGroup}>
+            <label className={styles.fieldLabel} htmlFor="feedback-content">
+              Describe your feedback
+            </label>
+            <div className={styles.textareaFrame}>
+              <textarea
+                id="feedback-content"
+                value={form.content}
+                maxLength={FEEDBACK_CONTENT_MAX_LENGTH}
+                disabled={form.isSubmitting}
+                className={styles.textarea}
+                placeholder="What happened, and what did you expect?"
+                onChange={(event) => form.setContent(event.target.value)}
+              />
+              <span className={styles.characterCount}>
+                {form.content.length}/{FEEDBACK_CONTENT_MAX_LENGTH}
+              </span>
+            </div>
+          </div>
+
+          <section className={styles.fieldGroup} aria-labelledby="feedback-images-label">
+            <div className={styles.imageHeading}>
+              <div>
+                <h2 id="feedback-images-label" className={styles.fieldLabel}>
+                  Add screenshots <span>Optional</span>
+                </h2>
+                <p className={styles.fieldHint}>JPEG, PNG or WebP · up to 5 MB each</p>
+              </div>
+              <span className={styles.imageCount}>
+                {form.images.length}/{FEEDBACK_IMAGE_LIMIT}
+              </span>
+            </div>
+
+            <div className={styles.imageGrid}>
+              {form.images.map((image, index) => (
+                <div className={styles.imagePreview} key={image.id}>
+                  <Image
+                    src={image.previewUrl}
+                    alt={`Feedback screenshot ${index + 1}`}
+                    fill
+                    unoptimized
+                    sizes="120px"
+                    className={styles.previewImage}
+                  />
+                  <button
+                    type="button"
+                    className={styles.removeImageButton}
+                    disabled={form.isSubmitting}
+                    aria-label={`Remove screenshot ${index + 1}`}
+                    onClick={() => form.removeImage(image.id)}
+                  >
+                    <Trash2 size={15} />
+                  </button>
+                </div>
+              ))}
+
+              {form.images.length < FEEDBACK_IMAGE_LIMIT ? (
+                <label
+                  className={`${styles.addImageButton} ${form.isPreparingImages ? styles.addImageButtonBusy : ""}`}
+                >
+                  <input
+                    type="file"
+                    multiple
+                    accept={FEEDBACK_IMAGE_ACCEPT}
+                    disabled={form.isPreparingImages || form.isSubmitting}
+                    className={styles.visuallyHidden}
+                    onChange={handleImageChange}
+                  />
+                  <ImagePlus size={23} strokeWidth={1.8} />
+                  <span>{form.isPreparingImages ? "Preparing..." : "Add image"}</span>
+                </label>
+              ) : null}
+            </div>
+          </section>
+
+          <div className={styles.statusSlot} aria-live="polite">
+            {form.errorMessage ? (
+              <p className={styles.errorMessage} role="alert">
+                {form.errorMessage}
+              </p>
+            ) : null}
+          </div>
+
+          <button
+            type="submit"
+            data-analytics-key="feedback.submit"
+            data-analytics-label="Submit feedback"
+            className={styles.primaryButton}
+            disabled={!form.canSubmit}
+          >
+            <Send size={18} strokeWidth={2.1} aria-hidden="true" />
+            <span>{form.isSubmitting ? "Sending feedback..." : "Send feedback"}</span>
+          </button>
+        </form>
+      </main>
+    </MobileShell>
+  );
+}
diff --git a/src/app/feedback/page.tsx b/src/app/feedback/page.tsx
new file mode 100644
index 00000000..05a668fc
--- /dev/null
+++ b/src/app/feedback/page.tsx
@@ -0,0 +1,5 @@
+import { FeedbackScreen } from "./feedback-screen";
+
+export default function FeedbackPage() {
+  return <FeedbackScreen />;
+}
diff --git a/src/app/feedback/use-feedback-submission.ts b/src/app/feedback/use-feedback-submission.ts
new file mode 100644
index 00000000..282c6bb6
--- /dev/null
+++ b/src/app/feedback/use-feedback-submission.ts
@@ -0,0 +1,152 @@
+"use client";
+
+import { type FormEvent, useEffect, useRef, useState } from "react";
+
+import type { FeedbackCategory } from "@/data/dto/feedback";
+import { submitFeedback } from "@/lib/feedback";
+
+import { createFeedbackContext } from "./feedback-context";
+import {
+  FEEDBACK_IMAGE_LIMIT,
+  prepareFeedbackImage,
+} from "./feedback-image";
+
+export const FEEDBACK_CONTENT_MIN_LENGTH = 10;
+export const FEEDBACK_CONTENT_MAX_LENGTH = 2000;
+
+export interface FeedbackImageItem {
+  id: string;
+  file: File;
+  previewUrl: string;
+}
+
+export function useFeedbackSubmission() {
+  const [category, setCategory] = useState<FeedbackCategory>("problem");
+  const [content, setContent] = useState("");
+  const [images, setImages] = useState<FeedbackImageItem[]>([]);
+  const [isPreparingImages, setIsPreparingImages] = useState(false);
+  const [isSubmitting, setIsSubmitting] = useState(false);
+  const [errorMessage, setErrorMessage] = useState<string | null>(null);
+  const [feedbackId, setFeedbackId] = useState<string | null>(null);
+  const imagesRef = useRef(images);
+
+  useEffect(() => {
+    imagesRef.current = images;
+  }, [images]);
+
+  useEffect(
+    () => () => {
+      imagesRef.current.forEach((image) => URL.revokeObjectURL(image.previewUrl));
+    },
+    [],
+  );
+
+  const addImages = async (files: FileList | readonly File[]) => {
+    if (isPreparingImages || isSubmitting) return;
+    const availableSlots = FEEDBACK_IMAGE_LIMIT - images.length;
+    if (availableSlots <= 0) {
+      setErrorMessage(`You can add up to ${FEEDBACK_IMAGE_LIMIT} images.`);
+      return;
+    }
+
+    const selectedFiles = Array.from(files);
+    const filesToPrepare = selectedFiles.slice(0, availableSlots);
+    const nextImages: FeedbackImageItem[] = [];
+    const errors: string[] = [];
+    setIsPreparingImages(true);
+    setErrorMessage(null);
+
+    for (const file of filesToPrepare) {
+      try {
+        const preparedFile = await prepareFeedbackImage(file);
+        nextImages.push({
+          id: createImageId(),
+          file: preparedFile,
+          previewUrl: URL.createObjectURL(preparedFile),
+        });
+      } catch (error) {
+        errors.push(error instanceof Error ? error.message : "Image processing failed.");
+      }
+    }
+
+    if (selectedFiles.length > availableSlots) {
+      errors.push(`You can add up to ${FEEDBACK_IMAGE_LIMIT} images.`);
+    }
+    setImages((current) => [...current, ...nextImages]);
+    setErrorMessage(errors[0] ?? null);
+    setIsPreparingImages(false);
+  };
+
+  const removeImage = (id: string) => {
+    if (isSubmitting) return;
+    setImages((current) => {
+      const image = current.find((item) => item.id === id);
+      if (image) URL.revokeObjectURL(image.previewUrl);
+      return current.filter((item) => item.id !== id);
+    });
+    setErrorMessage(null);
+  };
+
+  const submit = async (event: FormEvent<HTMLFormElement>) => {
+    event.preventDefault();
+    if (isSubmitting || isPreparingImages) return;
+
+    const normalizedContent = content.trim();
+    const validationError = validateFeedbackContent(normalizedContent);
+    if (validationError) {
+      setErrorMessage(validationError);
+      return;
+    }
+
+    setIsSubmitting(true);
+    setErrorMessage(null);
+    const result = await submitFeedback({
+      category,
+      content: normalizedContent,
+      context: createFeedbackContext(),
+      images: images.map((image) => image.file),
+    });
+
+    if (result.success) {
+      setFeedbackId(result.data.feedbackId);
+    } else {
+      setErrorMessage(result.error.message || "Feedback could not be sent. Please try again.");
+    }
+    setIsSubmitting(false);
+  };
+
+  return {
+    category,
+    content,
+    images,
+    isPreparingImages,
+    isSubmitting,
+    errorMessage,
+    feedbackId,
+    canSubmit:
+      validateFeedbackContent(content.trim()) === null &&
+      !isPreparingImages &&
+      !isSubmitting,
+    setCategory,
+    setContent,
+    addImages,
+    removeImage,
+    submit,
+  };
+}
+
+export function validateFeedbackContent(content: string): string | null {
+  if (content.length < FEEDBACK_CONTENT_MIN_LENGTH) {
+    return `Please enter at least ${FEEDBACK_CONTENT_MIN_LENGTH} characters.`;
+  }
+  if (content.length > FEEDBACK_CONTENT_MAX_LENGTH) {
+    return `Feedback cannot exceed ${FEEDBACK_CONTENT_MAX_LENGTH} characters.`;
+  }
+  return null;
+}
+
+function createImageId(): string {
+  return typeof crypto !== "undefined" && "randomUUID" in crypto
+    ? crypto.randomUUID()
+    : `${Date.now()}-${Math.random().toString(36).slice(2)}`;
+}
diff --git a/src/app/sidebar/components/sidebar-screen.module.css b/src/app/sidebar/components/sidebar-screen.module.css
index 7012d34e..d778e8ab 100644
--- a/src/app/sidebar/components/sidebar-screen.module.css
+++ b/src/app/sidebar/components/sidebar-screen.module.css
@@ -112,6 +112,11 @@
   background: rgba(255, 255, 255, 0.9);
 }
 
+.feedbackCard {
+  border-color: rgba(208, 150, 91, 0.16);
+  background: rgba(255, 253, 250, 0.92);
+}
+
 .logoutCard:hover {
   background: #ffffff;
   box-shadow: 0 16px 34px rgba(55, 36, 44, 0.1);
@@ -144,6 +149,11 @@
   color: #f657a0;
 }
 
+.feedbackIcon {
+  background: rgba(208, 150, 91, 0.13);
+  color: #b8783f;
+}
+
 .logoutText {
   display: flex;
   min-width: 0;
@@ -165,6 +175,13 @@
   line-height: 1.15;
 }
 
+.feedbackTitle {
+  color: #171114;
+  font-size: var(--responsive-body, 16px);
+  font-weight: 760;
+  line-height: 1.15;
+}
+
 .logoutSubtitle {
   color: #817076;
   font-size: var(--responsive-caption, 13px);
diff --git a/src/app/sidebar/sidebar-screen.tsx b/src/app/sidebar/sidebar-screen.tsx
index 06066fc4..adbe946c 100644
--- a/src/app/sidebar/sidebar-screen.tsx
+++ b/src/app/sidebar/sidebar-screen.tsx
@@ -1,6 +1,6 @@
 "use client";
 
-import { Download, LogOut } from "lucide-react";
+import { Download, LogOut, MessageCircleQuestion } from "lucide-react";
 import { signOut } from "next-auth/react";
 
 import { BackButton } from "@/app/_components";
@@ -99,6 +99,27 @@ export function SidebarScreen() {
           <section className={`${styles.settingsSlot} ${styles.revealThree}`}>
             <p className={styles.settingsLabel}>Other</p>
             <div className={styles.settingsActions}>
+              <button
+                type="button"
+                data-analytics-key="sidebar.open_feedback"
+                data-analytics-label="Open feedback"
+                className={`${styles.logoutCard} ${styles.feedbackCard}`}
+                onClick={() => navigator.push(ROUTES.feedback)}
+              >
+                <span
+                  className={`${styles.logoutIcon} ${styles.feedbackIcon}`}
+                  aria-hidden="true"
+                >
+                  <MessageCircleQuestion size={19} strokeWidth={2.2} />
+                </span>
+                <span className={styles.logoutText}>
+                  <span className={styles.feedbackTitle}>Feedback</span>
+                  <span className={styles.logoutSubtitle}>
+                    Report a problem or share an idea
+                  </span>
+                </span>
+              </button>
+
               {pwaInstallEntry.canInstall ? (
                 <button
                   type="button"
diff --git a/src/data/dto/feedback/feedback_submission.ts b/src/data/dto/feedback/feedback_submission.ts
new file mode 100644
index 00000000..49b2d68a
--- /dev/null
+++ b/src/data/dto/feedback/feedback_submission.ts
@@ -0,0 +1,22 @@
+export const FEEDBACK_CATEGORIES = [
+  "problem",
+  "suggestion",
+  "payment",
+  "other",
+] as const;
+
+export type FeedbackCategory = (typeof FEEDBACK_CATEGORIES)[number];
+
+export interface FeedbackContext {
+  appVersion: string;
+  platform: string;
+  browser: string;
+  viewport: string;
+}
+
+export interface SubmitFeedbackInput {
+  category: FeedbackCategory;
+  content: string;
+  context: FeedbackContext;
+  images: readonly File[];
+}
diff --git a/src/data/dto/feedback/index.ts b/src/data/dto/feedback/index.ts
new file mode 100644
index 00000000..8392624c
--- /dev/null
+++ b/src/data/dto/feedback/index.ts
@@ -0,0 +1,2 @@
+export * from "./feedback_submission";
+export * from "./response";
diff --git a/src/data/dto/feedback/response/feedback_submit_response.ts b/src/data/dto/feedback/response/feedback_submit_response.ts
new file mode 100644
index 00000000..e0956402
--- /dev/null
+++ b/src/data/dto/feedback/response/feedback_submit_response.ts
@@ -0,0 +1,26 @@
+import {
+  FeedbackSubmitResponseSchema,
+  type FeedbackSubmitResponseData,
+  type FeedbackSubmitResponseInput,
+} from "@/data/schemas/feedback";
+
+export class FeedbackSubmitResponse {
+  declare readonly feedbackId: string;
+
+  private constructor(input: FeedbackSubmitResponseInput) {
+    Object.assign(this, FeedbackSubmitResponseSchema.parse(input));
+    Object.freeze(this);
+  }
+
+  static from(input: FeedbackSubmitResponseInput): FeedbackSubmitResponse {
+    return new FeedbackSubmitResponse(input);
+  }
+
+  static fromJson(json: unknown): FeedbackSubmitResponse {
+    return FeedbackSubmitResponse.from(json as FeedbackSubmitResponseInput);
+  }
+
+  toJson(): FeedbackSubmitResponseData {
+    return FeedbackSubmitResponseSchema.parse(this);
+  }
+}
diff --git a/src/data/dto/feedback/response/index.ts b/src/data/dto/feedback/response/index.ts
new file mode 100644
index 00000000..338edb5d
--- /dev/null
+++ b/src/data/dto/feedback/response/index.ts
@@ -0,0 +1 @@
+export * from "./feedback_submit_response";
diff --git a/src/data/repositories/feedback_repository.ts b/src/data/repositories/feedback_repository.ts
new file mode 100644
index 00000000..bea54888
--- /dev/null
+++ b/src/data/repositories/feedback_repository.ts
@@ -0,0 +1,21 @@
+import type {
+  FeedbackSubmitResponse,
+  SubmitFeedbackInput,
+} from "@/data/dto/feedback";
+import type { IFeedbackRepository } from "@/data/repositories/interfaces";
+import { FeedbackApi, feedbackApi } from "@/data/services/api/feedback_api";
+import { Result } from "@/utils/result";
+
+import { createLazySingleton } from "./lazy_singleton";
+
+export class FeedbackRepository implements IFeedbackRepository {
+  constructor(private readonly api: FeedbackApi) {}
+
+  submit(input: SubmitFeedbackInput): Promise<Result<FeedbackSubmitResponse>> {
+    return Result.wrap(() => this.api.submit(input));
+  }
+}
+
+export const getFeedbackRepository = createLazySingleton<IFeedbackRepository>(
+  () => new FeedbackRepository(feedbackApi),
+);
diff --git a/src/data/repositories/index.ts b/src/data/repositories/index.ts
index 0dea2574..63e6d15a 100644
--- a/src/data/repositories/index.ts
+++ b/src/data/repositories/index.ts
@@ -4,12 +4,14 @@
 
 export * from "./auth_repository";
 export * from "./chat_repository";
+export * from "./feedback_repository";
 export * from "./metrics_repository";
 export * from "./payment_repository";
 export * from "./private_room_repository";
 export * from "./user_repository";
 export * from "./interfaces/iauth_repository";
 export * from "./interfaces/ichat_repository";
+export * from "./interfaces/ifeedback_repository";
 export * from "./interfaces/imetrics_repository";
 export * from "./interfaces/ipayment_repository";
 export * from "./interfaces/iprivate_room_repository";
diff --git a/src/data/repositories/interfaces/ifeedback_repository.ts b/src/data/repositories/interfaces/ifeedback_repository.ts
new file mode 100644
index 00000000..323952ae
--- /dev/null
+++ b/src/data/repositories/interfaces/ifeedback_repository.ts
@@ -0,0 +1,9 @@
+import type {
+  FeedbackSubmitResponse,
+  SubmitFeedbackInput,
+} from "@/data/dto/feedback";
+import type { Result } from "@/utils/result";
+
+export interface IFeedbackRepository {
+  submit(input: SubmitFeedbackInput): Promise<Result<FeedbackSubmitResponse>>;
+}
diff --git a/src/data/repositories/interfaces/index.ts b/src/data/repositories/interfaces/index.ts
index d5877353..c109eec7 100644
--- a/src/data/repositories/interfaces/index.ts
+++ b/src/data/repositories/interfaces/index.ts
@@ -4,6 +4,7 @@
 
 export * from "./iauth_repository";
 export * from "./ichat_repository";
+export * from "./ifeedback_repository";
 export * from "./imetrics_repository";
 export * from "./ipayment_repository";
 export * from "./iprivate_room_repository";
diff --git a/src/data/schemas/feedback/index.ts b/src/data/schemas/feedback/index.ts
new file mode 100644
index 00000000..9d2cfb1f
--- /dev/null
+++ b/src/data/schemas/feedback/index.ts
@@ -0,0 +1 @@
+export * from "./response";
diff --git a/src/data/schemas/feedback/response/feedback_submit_response.ts b/src/data/schemas/feedback/response/feedback_submit_response.ts
new file mode 100644
index 00000000..8fd7ca95
--- /dev/null
+++ b/src/data/schemas/feedback/response/feedback_submit_response.ts
@@ -0,0 +1,12 @@
+import { z } from "zod";
+
+export const FeedbackSubmitResponseSchema = z.object({
+  feedbackId: z.string().min(1),
+});
+
+export type FeedbackSubmitResponseInput = z.input<
+  typeof FeedbackSubmitResponseSchema
+>;
+export type FeedbackSubmitResponseData = z.output<
+  typeof FeedbackSubmitResponseSchema
+>;
diff --git a/src/data/schemas/feedback/response/index.ts b/src/data/schemas/feedback/response/index.ts
new file mode 100644
index 00000000..338edb5d
--- /dev/null
+++ b/src/data/schemas/feedback/response/index.ts
@@ -0,0 +1 @@
+export * from "./feedback_submit_response";
diff --git a/src/data/services/api/__tests__/feedback_api.test.ts b/src/data/services/api/__tests__/feedback_api.test.ts
new file mode 100644
index 00000000..1f979b66
--- /dev/null
+++ b/src/data/services/api/__tests__/feedback_api.test.ts
@@ -0,0 +1,53 @@
+import { beforeEach, describe, expect, it, vi } from "vitest";
+
+const httpClientMock = vi.hoisted(() => vi.fn());
+
+vi.mock("../http_client", () => ({
+  httpClient: httpClientMock,
+}));
+
+import { FeedbackApi } from "../feedback_api";
+
+describe("FeedbackApi", () => {
+  beforeEach(() => {
+    httpClientMock.mockReset();
+  });
+
+  it("submits the supported fields as multipart data", async () => {
+    httpClientMock.mockResolvedValue({
+      success: true,
+      data: { feedbackId: "feedback-123", ignored: "server-only" },
+    });
+    const image = new File(["image"], "screen.jpg", {
+      type: "image/jpeg",
+    });
+
+    const response = await new FeedbackApi().submit({
+      category: "problem",
+      content: "The send button did not respond.",
+      context: {
+        appVersion: "0.1.0",
+        platform: "android Android 15",
+        browser: "facebook IAB / Chrome 135",
+        viewport: "392x760@2.75",
+      },
+      images: [image],
+    });
+
+    expect(response.toJson()).toEqual({ feedbackId: "feedback-123" });
+    expect(httpClientMock).toHaveBeenCalledWith(
+      "/api/feedback",
+      expect.objectContaining({ method: "POST", body: expect.any(FormData) }),
+    );
+    const body = httpClientMock.mock.calls[0][1].body as FormData;
+    expect(body.get("category")).toBe("problem");
+    expect(body.get("content")).toBe("The send button did not respond.");
+    expect(JSON.parse(String(body.get("context")))).toEqual({
+      appVersion: "0.1.0",
+      platform: "android Android 15",
+      browser: "facebook IAB / Chrome 135",
+      viewport: "392x760@2.75",
+    });
+    expect(body.getAll("images")).toEqual([image]);
+  });
+});
diff --git a/src/data/services/api/__tests__/http_client.test.ts b/src/data/services/api/__tests__/http_client.test.ts
index ac4c7062..1612c588 100644
--- a/src/data/services/api/__tests__/http_client.test.ts
+++ b/src/data/services/api/__tests__/http_client.test.ts
@@ -22,6 +22,13 @@ function callUrl(call: Parameters<typeof fetch>): URL {
   return new URL(request instanceof Request ? request.url : String(request));
 }
 
+function callHeaders(call: Parameters<typeof fetch>): Headers {
+  const [request, init] = call;
+  return request instanceof Request
+    ? request.headers
+    : new Headers(init?.headers);
+}
+
 describe("createHttpClient", () => {
   beforeEach(() => {
     process.env.NEXT_PUBLIC_API_BASE_URL = "https://api.example.test";
@@ -264,4 +271,35 @@ describe("createHttpClient", () => {
     ]);
     await expect(authStorage.getGuestToken()).resolves.toEqual(Result.ok(null));
   });
+
+  it("lets ofetch set JSON content headers for object bodies", async () => {
+    const fetchMock = vi.fn<typeof fetch>(async () =>
+      jsonResponse({ success: true }),
+    );
+    vi.stubGlobal("fetch", fetchMock);
+
+    const http = createHttpClient();
+    await http("/api/example", {
+      method: "POST",
+      body: { message: "hello" },
+    });
+
+    expect(callHeaders(fetchMock.mock.calls[0]).get("Content-Type")).toContain(
+      "application/json",
+    );
+  });
+
+  it("does not override multipart boundaries for FormData bodies", async () => {
+    const fetchMock = vi.fn<typeof fetch>(async () =>
+      jsonResponse({ success: true }),
+    );
+    vi.stubGlobal("fetch", fetchMock);
+    const body = new FormData();
+    body.append("content", "feedback");
+
+    const http = createHttpClient();
+    await http("/api/feedback", { method: "POST", body });
+
+    expect(callHeaders(fetchMock.mock.calls[0]).get("Content-Type")).toBeNull();
+  });
 });
diff --git a/src/data/services/api/api_path.ts b/src/data/services/api/api_path.ts
index 24e5153b..56110f54 100644
--- a/src/data/services/api/api_path.ts
+++ b/src/data/services/api/api_path.ts
@@ -103,4 +103,7 @@ export class ApiPath {
 
   /** 上报用户信息 */
   static readonly reportUserInfo = `${ApiPath._data}/report-user-info`;
+
+  // ============ 用户反馈相关 ============
+  static readonly feedback = `${ApiPath._baseUrl}/feedback`;
 }
diff --git a/src/data/services/api/feedback_api.ts b/src/data/services/api/feedback_api.ts
new file mode 100644
index 00000000..29a66083
--- /dev/null
+++ b/src/data/services/api/feedback_api.ts
@@ -0,0 +1,26 @@
+import {
+  FeedbackSubmitResponse,
+  type SubmitFeedbackInput,
+} from "@/data/dto/feedback";
+
+import { ApiPath } from "./api_path";
+import { httpClient } from "./http_client";
+import { type ApiEnvelope, unwrap } from "./response_helper";
+
+export class FeedbackApi {
+  async submit(input: SubmitFeedbackInput): Promise<FeedbackSubmitResponse> {
+    const body = new FormData();
+    body.append("category", input.category);
+    body.append("content", input.content);
+    body.append("context", JSON.stringify(input.context));
+    input.images.forEach((image) => body.append("images", image));
+
+    const envelope = await httpClient<ApiEnvelope<unknown>>(ApiPath.feedback, {
+      method: "POST",
+      body,
+    });
+    return FeedbackSubmitResponse.fromJson(unwrap(envelope));
+  }
+}
+
+export const feedbackApi = new FeedbackApi();
diff --git a/src/data/services/api/http_client.ts b/src/data/services/api/http_client.ts
index 2035ea3c..03f24824 100644
--- a/src/data/services/api/http_client.ts
+++ b/src/data/services/api/http_client.ts
@@ -44,9 +44,6 @@ export function createHttpClient(): $Fetch {
     timeout: config.receiveTimeout,
     retry: 1, // 401 刷新后由 ofetch 重放一次原请求
     retryStatusCodes: [ErrorCode.httpUnauthorized],
-    headers: {
-      "Content-Type": "application/json",
-    },
     onRequest: chain(
       loggingInterceptor.onRequest,
       tokenInterceptor.onRequest
diff --git a/src/data/services/api/index.ts b/src/data/services/api/index.ts
index 34fd9242..56903766 100644
--- a/src/data/services/api/index.ts
+++ b/src/data/services/api/index.ts
@@ -6,6 +6,7 @@ export * from "./api_path";
 export * from "./api_result";
 export * from "./auth_api";
 export * from "./chat_api";
+export * from "./feedback_api";
 export * from "./http_client";
 export * from "./metrics_api";
 export * from "./payment_api";
diff --git a/src/lib/feedback/index.ts b/src/lib/feedback/index.ts
new file mode 100644
index 00000000..3f723f76
--- /dev/null
+++ b/src/lib/feedback/index.ts
@@ -0,0 +1 @@
+export * from "./submit_feedback";
diff --git a/src/lib/feedback/submit_feedback.ts b/src/lib/feedback/submit_feedback.ts
new file mode 100644
index 00000000..f1947865
--- /dev/null
+++ b/src/lib/feedback/submit_feedback.ts
@@ -0,0 +1,12 @@
+import type {
+  FeedbackSubmitResponse,
+  SubmitFeedbackInput,
+} from "@/data/dto/feedback";
+import { getFeedbackRepository } from "@/data/repositories";
+import type { Result } from "@/utils/result";
+
+export function submitFeedback(
+  input: SubmitFeedbackInput,
+): Promise<Result<FeedbackSubmitResponse>> {
+  return getFeedbackRepository().submit(input);
+}
diff --git a/src/router/__tests__/route-meta.test.ts b/src/router/__tests__/route-meta.test.ts
index 5a78f0cb..8ebd1f98 100644
--- a/src/router/__tests__/route-meta.test.ts
+++ b/src/router/__tests__/route-meta.test.ts
@@ -12,6 +12,7 @@ describe("route meta", () => {
     expect(getRouteAccess(ROUTES.tip)).toBe("public");
     expect(getRouteAccess(ROUTES.externalEntry)).toBe("public");
     expect(getRouteAccess(ROUTES.sidebar)).toBe("session");
+    expect(getRouteAccess(ROUTES.feedback)).toBe("session");
     expect(getRouteAccess(ROUTES.subscription)).toBe("realUser");
     expect(getRouteAccess(ROUTES.coinsRules)).toBe("public");
   });
@@ -32,6 +33,10 @@ describe("route meta", () => {
     expect(ALL_STATIC_ROUTES).toContain(ROUTES.externalEntry);
   });
 
+  it("includes feedback in static routes", () => {
+    expect(ALL_STATIC_ROUTES).toContain(ROUTES.feedback);
+  });
+
   it("treats unknown routes as public by default", () => {
     expect(getRouteAccess("/unknown")).toBe("public");
   });
diff --git a/src/router/route-meta.ts b/src/router/route-meta.ts
index 4371b7d6..100ef6bb 100644
--- a/src/router/route-meta.ts
+++ b/src/router/route-meta.ts
@@ -16,6 +16,7 @@ const STATIC_ROUTE_ACCESS: Partial<Record<string, RouteAccess>> = {
   [ROUTES.tip]: "public",
   [ROUTES.externalEntry]: "public",
   [ROUTES.sidebar]: "session",
+  [ROUTES.feedback]: "session",
   [ROUTES.subscription]: "realUser",
   [ROUTES.coinsRules]: "public",
 };
diff --git a/src/router/routes.ts b/src/router/routes.ts
index 0909e76b..ee7fa660 100644
--- a/src/router/routes.ts
+++ b/src/router/routes.ts
@@ -25,6 +25,7 @@ export const ROUTES = {
   externalEntry: "/external-entry",
   auth: "/auth",
   sidebar: "/sidebar",
+  feedback: "/feedback",
   subscription: "/subscription",
   coinsRules: "/coins-rules",
 } as const;
@@ -69,6 +70,7 @@ export const ALL_STATIC_ROUTES: readonly StaticRoute[] = [
   ROUTES.externalEntry,
   ROUTES.auth,
   ROUTES.sidebar,
+  ROUTES.feedback,
   ROUTES.coinsRules,
 ] as const;