---
id: warnings
title: Warnings
---

This is a list of warning output from NextAuth.js.

All warnings indicate things which you should take a look at, but do not inhibit normal operation.

---

## Client

#### NEXTAUTH_URL

Environment variable `NEXTAUTH_URL` missing. Please set it in your `.env` file.

:::note
On [Vercel](https://vercel.com) deployments, we will read the `VERCEL_URL` environment variable, so you won't need to define `NEXTAUTH_URL`.
:::

---

## Server

These warnings are displayed on the terminal.

#### NO_SECRET

In development, we generate a `secret` based on your configuration for convenience. This is volatile and will throw an error in production. [Read more](https://next-auth.js.org/configuration/options#secret)

#### TWITTER_OAUTH_2_BETA

Twitter OAuth 2.0 is currently in beta as certain changes might still be necessary. This is not covered by semver. See the docs https://next-auth.js.org/providers/twitter#oauth-2

#### EXPERIMENTAL_API

Some APIs are still experimental; they may be changed or removed in the future. Use at your own risk.

#### DEBUG_ENABLED

You have enabled the `debug` option. It is meant for development only, to help you catch issues in your authentication flow and you should consider removing this option when deploying to production. One way of only allowing debugging while not in production is to set `debug: process.env.NODE_ENV !== "production"`, so you can commit this without needing to change the value.

If you want to log debug messages during production anyway, we recommend setting the [`logger` option](/configuration/options#logger) with proper sanitization of potentially sensitive user information.

## Adapter

### ADAPTER_TYPEORM_UPDATING_ENTITIES

This warning occurs when typeorm finds that the provided entities differ from the database entities. By default while not in `production` the typeorm adapter will always synchronize changes made to the entities codefiles.

Disable this warning by setting `synchronize: false` in your typeorm config

Example:

```js title="/pages/api/auth/[...nextauth].js"
adapter: TypeORMLegacyAdapter({
  type: 'mysql',
  username: process.env.DATABASE_USERNAME,
  password: process.env.DATABASE_PASSWORD,
  host: process.env.DATABASE_HOST,
  database: process.env.DATABASE_DB,
  synchronize: false
}),
```
