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

# Identify

> Identify users in Next.js (client and server)

# Next.js — Identify

Identify users from client components (using React hooks) or from the server. On the server, pass `sessionId` and `windowId` from request headers when you have them so events stay correlated with the client session.

## Client: useSignalIdentify

Use the same hook as the [React integration](/docs/integrations/react/identify), re-exported from `@signal-js/nextjs/client`:

```tsx theme={null}
'use client';

import { useSignalIdentify } from '@signal-js/nextjs/client';

export function LoginForm() {
  const { identify, reset } = useSignalIdentify();

  const handleLogin = (user) => {
    identify(user.id, { email: user.email, name: user.name });
  };

  const handleLogout = () => {
    reset();
  };

  return (
    <>
      <button onClick={() => handleLogin({ id: 'user_123', email: 'j@example.com', name: 'Jane' })}>
        Log in
      </button>
      <button onClick={handleLogout}>Log out</button>
    </>
  );
}
```

## Server: identify(options)

From API routes or Server Actions, call `signal.identify()` with an options object. Include `sessionId` and `windowId` from the request when you want to tie the identify to the same browser session:

```typescript theme={null}
import { signal, getSessionInfo } from '@/lib/signal-server';

// In an API route or Server Action after reading headers:
const { sessionId, windowId, distinctId } = getSessionInfo(request);

signal.identify({
  distinctId: userId,
  properties: { email: 'user@example.com', name: 'Jane' },
  sessionId,
  windowId,
});
```

## See also

* [Capture](/docs/integrations/nextjs/capture) — Track events
* [Initialization](/docs/integrations/nextjs/initialization) — Server client setup