# General Translation React SDKs (gt-react, gt-next, gt-react-native): Registering request locales
URL: https://generaltranslation.com/en-US/docs/react/nextjs/registering-request-locales.mdx
Docs index: https://generaltranslation.com/llms.txt
Description: How to register a locale for Next.js App Router route handlers and generated metadata images with General Translation.

With a root `[locale]` segment, `gt-next` normally reads the locale through `next/root-params`. Route Handlers and generated metadata image handlers cannot use that module. Read the locale from the handler input, then call [`registerLocale`](/docs/react/nextjs/reference/functions/register-locale) before any other `gt-next/server` function.

## Register a Route Handler [#route-handlers]

For a handler below `app/[locale]`, read the locale from `params`:

```ts title="app/[locale]/api/greeting/route.ts"
import { getGT, registerLocale } from 'gt-next/server';

export async function GET(
  _request: Request,
  { params }: { params: Promise<{ locale: string }> },
) {
  const { locale } = await params;
  registerLocale(locale);

  const gt = await getGT();
  return Response.json({ greeting: gt('Welcome') });
}
```

For a handler outside `[locale]`, derive the locale from the `Request` URL, headers, query parameters, or body according to your API, then register it the same way.

The registered locale is available to [`getGT`](/docs/react/nextjs/reference/functions/get-gt), [`getLocale`](/docs/react/nextjs/reference/functions/get-locale), [`getTranslations`](/docs/react/nextjs/reference/functions/get-translations), [`getMessages`](/docs/react/nextjs/reference/functions/get-messages), and other `gt-next/server` functions for the rest of the request.

## Register a metadata image handler [#metadata-images]

Generated Open Graph, Twitter, icon, and Apple icon files also receive route `params`:

```tsx title="app/[locale]/opengraph-image.tsx"
import { ImageResponse } from 'next/og';
import { getGT, registerLocale } from 'gt-next/server';

export default async function Image({
  params,
}: {
  params: Promise<{ locale: string }>;
}) {
  const { locale } = await params;
  registerLocale(locale);

  const gt = await getGT();
  return new ImageResponse(<div>{gt('Welcome')}</div>);
}
```

Use the same pattern in `twitter-image.tsx`, `icon.tsx`, and `apple-icon.tsx`.

## Handle other entry points [#other-entry-points]

`generateMetadata` receives dynamic route parameters from the root through its current segment, so it does not have the same limitation as a metadata image handler.

Generated `sitemap.ts`, `robots.ts`, and `manifest.ts` files do not receive route parameters or a request object. Choose the locale explicitly in your generation logic, then register it before calling a `gt-next/server` function.

Registration is request-scoped. Call [`registerLocale`](/docs/react/nextjs/reference/functions/register-locale) once, after resolving the locale and before any other General Translation server function.

## Next steps

- /docs/react/nextjs/reference/functions/register-locale
- /docs/react/nextjs/app-router-middleware
- /docs/react/nextjs/reference/functions/get-locale
- /docs/react/nextjs/reference/functions/get-gt

## Sitemap

See the full [sitemap](https://generaltranslation.com/sitemap.md) for all pages.