> ## Documentation Index
> Fetch the complete documentation index at: https://committ.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Middleware & Auth

> Authentication guards and request validation using Better Auth.

# Middleware & Authentication

The `backend/convex/middleware/` directory ensures that every request hitting the CommitT backend is secure, authenticated, and authorized.

## Better Auth Integration

CommitT uses [Better Auth](https://better-auth.com/) for cross-platform identity management, integrated natively with Convex via the `@convex-dev/better-auth` plugin.

Located in `middleware/auth.ts`:

```typescript theme={null}
import { expo } from "@better-auth/expo";
import { convex } from "@convex-dev/better-auth/plugins";
import { betterAuth } from "better-auth";

function createAuth(ctx) {
  return betterAuth({
    trustedOrigins: [siteUrl, nativeAppUrl], // Allows web and mobile deep links
    emailAndPassword: { enabled: true },
    socialProviders: { google: { /* ... */ } },
    plugins: [ expo(), convex({ authConfig }) ],
  });
}
```

## API Guards

Instead of checking auth state manually in every endpoint, the backend exports strongly-typed middleware wrappers:

* `authedMutation`
* `authedQuery`

These wrappers guarantee that the `ctx.user` object is populated before the endpoint logic executes. If a user is unauthenticated, the request is instantly rejected, preventing unauthorized access to the core logic layer.