---
createdAt: 2024-12-06
updatedAt: 2025-12-30
title: Next.js i18n - How to translate an Next.js 15 app in 2026
description: Discover how to make your Next.js 15 website multilingual. Follow the documentation to internationalise (i18n) and translate it.
keywords:
  - Internationalisation
  - Documentation
  - Intlayer
  - Next.js 15
  - JavaScript
  - React
slugs:
  - doc
  - environment
  - nextjs
  - 15
applicationTemplate: https://github.com/aymericzip/intlayer-next-15-template
youtubeVideo: https://www.youtube.com/watch?v=e_PPG7PTqGU
history:
  - version: 7.5.9
    date: 2025-12-30
    changes: Add init command
  - version: 5.5.10
    date: 2025-06-29
    changes: Init history
---

# Getting Started internationalising (i18n) with Intlayer and Next.js 15 App Router

<iframe title="The best i18n solution for Next.js? Discover Intlayer" class="m-auto aspect-16/9 w-full overflow-hidden rounded-lg border-0" allow="autoplay; gyroscope;" loading="lazy" width="1080" height="auto" src="https://www.youtube.com/embed/e_PPG7PTqGU?autoplay=0&amp;origin=http://intlayer.org&amp;controls=0&amp;rel=1"/>

See [Application Template](https://github.com/aymericzip/intlayer-next-15-template) on GitHub.

## What is Intlayer?

**Intlayer** is an innovative, open-source internationalisation (i18n) library designed to simplify multilingual support in modern web applications. Intlayer seamlessly integrates with the latest **Next.js 15** framework, including its powerful **App Router**. It is optimised to work with **Server Components** for efficient rendering and is fully compatible with [**Turbopack**](https://nextjs.org/docs/architecture/turbopack).

With Intlayer, you can:

- **Easily manage translations** using declarative dictionaries at the component level.
- **Dynamically localise metadata**, routes, and content.
- **Access translations in both client-side and server-side components**.
- **Ensure TypeScript support** with autogenerated types, improving autocompletion and error detection.
- **Benefit from advanced features**, such as dynamic locale detection and switching.

> Intlayer is compatible with Next.js 12, 13, 14, and 15. If you are using the Next.js Page Router, you can refer to this [guide](https://github.com/aymericzip/intlayer/blob/main/docs/docs/en-GB/intlayer_with_nextjs_page_router.md). For Next.js 12, 13, 14 with the App Router, refer to this [guide](https://github.com/aymericzip/intlayer/blob/main/docs/docs/en-GB/intlayer_with_nextjs_14.md).

---

## Step-by-Step Guide to Set Up Intlayer in a Next.js Application

### Step 1: Install Dependencies

Install the necessary packages using npm:

```bash packageManager="npm"
npm install intlayer next-intlayer
npx intlayer init
```

```bash packageManager="pnpm"
pnpm add intlayer next-intlayer
pnpm intlayer init
```

```bash packageManager="yarn"
yarn add intlayer next-intlayer
yarn intlayer init
```

```bash packageManager="bun"
bun add intlayer next-intlayer
bunx intlayer init
```

- **intlayer**

  The core package that provides internationalisation tools for configuration management, translation, [content declaration](https://github.com/aymericzip/intlayer/blob/main/docs/docs/en-GB/dictionary/content_file.md), transpilation, and [CLI commands](https://github.com/aymericzip/intlayer/blob/main/docs/docs/en-GB/cli/index.md).

- **next-intlayer**

  The package that integrates Intlayer with Next.js. It provides context providers and hooks for Next.js internationalisation. Additionally, it includes the Next.js plugin for integrating Intlayer with [Webpack](https://webpack.js.org/) or [Turbopack](https://nextjs.org/docs/app/api-reference/turbopack), as well as middleware for detecting the user's preferred locale, managing cookies, and handling URL redirection.

### Step 2: Configure Your Project

Here is the final structure that we will make:

```bash
.
├── src
│   ├── app
│   │   ├── [locale]
│   │   │   ├── layout.tsx            # Locale layout for the Intlayer provider
│   │   │   ├── page.content.ts
│   │   │   └── page.tsx
│   │   └── layout.tsx                # Root layout for style and global providers
│   ├── components
│   │   ├── client-component-example.content.ts
│   │   ├── ClientComponentExample.tsx
│   │   ├── LocaleSwitcher
│   │   │   ├── localeSwitcher.content.ts
│   │   │   └── LocaleSwitcher.tsx
│   │   ├── server-component-example.content.ts
│   │   └── ServerComponentExample.tsx
│   └── middleware.ts
├── intlayer.config.ts
├── next.config.ts
├── package.json
└── tsconfig.json
```

> If you don't want locale routing, intlayer can be used as a simple provider / hook. See [this guide](https://github.com/aymericzip/intlayer/blob/main/docs/docs/en/intlayer_with_nextjs_no_locale_path.md) for more details.

Create a config file to configure the languages of your application:

```typescript fileName="intlayer.config.ts" codeFormat="typescript"
import { Locales, type IntlayerConfig } from "intlayer";

const config: IntlayerConfig = {
  internationalization: {
    locales: [
      Locales.ENGLISH,
      Locales.FRENCH,
      Locales.SPANISH,
      // Your other locales
    ],
    defaultLocale: Locales.ENGLISH,
  },
};

export default config;
```

```javascript fileName="intlayer.config.mjs" codeFormat="esm"
import { Locales } from "intlayer";

/** @type {import('intlayer').IntlayerConfig} */
const config = {
  internationalization: {
    locales: [
      Locales.ENGLISH,
      Locales.FRENCH,
      Locales.SPANISH,
      // Your other locales
    ],
    defaultLocale: Locales.ENGLISH,
  },
};

export default config;
```

```javascript fileName="intlayer.config.cjs" codeFormat="commonjs"
const { Locales } = require("intlayer");

/** @type {import('intlayer').IntlayerConfig} */
const config = {
  internationalization: {
    locales: [
      Locales.ENGLISH,
      Locales.FRENCH,
      Locales.SPANISH,
      // Your other locales
    ],
    defaultLocale: Locales.ENGLISH,
  },
};

module.exports = config;
```

> Through this configuration file, you can set up localised URLs, middleware redirection, cookie names, the location and extension of your content declarations, disable Intlayer logs in the console, and more. For a complete list of available parameters, refer to the [configuration documentation](https://github.com/aymericzip/intlayer/blob/main/docs/docs/en-GB/configuration.md).

### Step 3: Integrate Intlayer in Your Next.js Configuration

Configure your Next.js setup to use Intlayer:

```typescript fileName="next.config.ts" codeFormat="typescript"
import type { NextConfig } from "next";
import { withIntlayer } from "next-intlayer/server";

const nextConfig: NextConfig = {
  /* config options here */
};

export default withIntlayer(nextConfig);
```

```typescript fileName="next.config.mjs" codeFormat="esm"
import { withIntlayer } from "next-intlayer/server";

/** @type {import('next').NextConfig} */
const nextConfig = {
  /* config options here */
};

export default withIntlayer(nextConfig);
```

```typescript fileName="next.config.cjs" codeFormat="commonjs"
const { withIntlayer } = require("next-intlayer/server");

/** @type {import('next').NextConfig} */
const nextConfig = {
  /* config options here */
};

module.exports = withIntlayer(nextConfig);
```

> The `withIntlayer()` Next.js plugin is used to integrate Intlayer with Next.js. It ensures the building of content declaration files and monitors them in development mode. It defines Intlayer environment variables within the [Webpack](https://webpack.js.org/) or [Turbopack](https://nextjs.org/docs/app/api-reference/turbopack) environments. Additionally, it provides aliases to optimise performance and ensures compatibility with server components.

### Step 4: Define Dynamic Locale Routes

Remove everything from `RootLayout` and replace it with the following code:

```tsx {3} fileName="src/app/layout.tsx" codeFormat="typescript"
import type { PropsWithChildren, FC } from "react";
import "./globals.css";

const RootLayout: FC<PropsWithChildren> = ({ children }) => children;

export default RootLayout;
```

```jsx {3} fileName="src/app/layout.mjx" codeFormat="esm"
import "./globals.css";

const RootLayout = ({ children }) => children;

export default RootLayout;
```

```jsx {1,8} fileName="src/app/layout.csx" codeFormat="commonjs"
require("./globals.css");

const RootLayout = ({ children }) => children;

module.exports = {
  default: RootLayout,
  generateStaticParams,
};
```

> Keeping the `RootLayout` component empty allows setting the [`lang`](https://developer.mozilla.org/fr/docs/Web/HTML/Global_attributes/lang) and [`dir`](https://developer.mozilla.org/fr/docs/Web/HTML/Global_attributes/dir) attributes on the `<html>` tag.

To implement dynamic routing, provide the path for the locale by adding a new layout in your `[locale]` directory:

```tsx fileName="src/app/[locale]/layout.tsx" codeFormat="typescript"
import type { NextLayoutIntlayer } from "next-intlayer";
import { Inter } from "next/font/google";
import { getHTMLTextDir } from "intlayer";

const inter = Inter({ subsets: ["latin"] });

const LocaleLayout: NextLayoutIntlayer = async ({ children, params }) => {
  const { locale } = await params;
  return (
    <html lang={locale} dir={getHTMLTextDir(locale)}>
      <body className={inter.className}>{children}</body>
    </html>
  );
};

export default LocaleLayout;
```

```jsx fileName="src/app/[locale]/layout.mjx" codeFormat="esm"
import { getHTMLTextDir } from "intlayer";

const inter = Inter({ subsets: ["latin"] });

const LocaleLayout = async ({ children, params: { locale } }) => {
  const { locale } = await params;
  return (
    <html lang={locale} dir={getHTMLTextDir(locale)}>
      <body className={inter.className}>{children}</body>
    </html>
  );
};

export default LocaleLayout;
```

```jsx fileName="src/app/[locale]/layout.csx" codeFormat="commonjs"
const { Inter } = require("next/font/google");
const { getHTMLTextDir } = require("intlayer");

const inter = Inter({ subsets: ["latin"] });

const LocaleLayout = async ({ children, params: { locale } }) => {
  const { locale } = await params;
  return (
    <html lang={locale} dir={getHTMLTextDir(locale)}>
      <body className={inter.className}>{children}</body>
    </html>
  );
};

module.exports = LocaleLayout;
```

> The `[locale]` path segment is used to define the locale. Example: `/en-US/about` will refer to `en-US` and `/fr/about` to `fr`.

> At this stage, you will encounter the error: `Error: Missing <html> and <body> tags in the root layout.`. This is expected because the `/app/page.tsx` file is no longer in use and can be removed. Instead, the `[locale]` path segment will activate the `/app/[locale]/page.tsx` page. Consequently, pages will be accessible via paths like `/en`, `/fr`, `/es` in your browser. To set the default locale as the root page, refer to the `middleware` setup in step 7.

Then, implement the `generateStaticParams` function in your application Layout.

```tsx {1} fileName="src/app/[locale]/layout.tsx" codeFormat="typescript"
export { generateStaticParams } from "next-intlayer"; // Line to insert

const LocaleLayout: NextLayoutIntlayer = async ({ children, params }) => {
  /*... Rest of the code*/
};

export default LocaleLayout;
```

```jsx {1} fileName="src/app/[locale]/layout.mjx" codeFormat="esm"
export { generateStaticParams } from "next-intlayer"; // Line to insert

const LocaleLayout = async ({ children, params: { locale } }) => {
  /*... Rest of the code*/
};

// ... Rest of the code
```

```jsx {1,7} fileName="src/app/[locale]/layout.csx" codeFormat="commonjs"
const { generateStaticParams } = require("next-intlayer"); // Line to insert

const LocaleLayout = async ({ children, params: { locale } }) => {
  /*... Rest of the code*/
};

module.exports = { default: LocaleLayout, generateStaticParams };
```

> `generateStaticParams` ensures that your application pre-builds the necessary pages for all locales, reducing runtime computation and improving the user experience. For more details, refer to the [Next.js documentation on generateStaticParams](https://nextjs.org/docs/app/building-your-application/rendering/static-and-dynamic-rendering#generate-static-params).

### Step 5: Declare Your Content

Create and manage your content declarations to store translations:

```tsx fileName="src/app/[locale]/page.content.ts" contentDeclarationFormat="typescript"
import { t, type Dictionary } from "intlayer";

const pageContent = {
  key: "page",
  content: {
    getStarted: {
      main: t({
        "en-GB": "Get started by editing",
        en: "Get started by editing",
        fr: "Commencez par éditer",
        es: "Comience por editar",
      }),
      pageLink: "src/app/page.tsx",
    },
  },
} satisfies Dictionary;

export default pageContent;
```

```javascript fileName="src/app/[locale]/page.content.mjs" contentDeclarationFormat="esm"
import { t } from "intlayer";

/** @type {import('intlayer').Dictionary} */
const pageContent = {
  key: "page",
  content: {
    getStarted: {
      main: t({
        "en-GB": "Get started by editing",
        en: "Get started by editing",
        fr: "Commencez par éditer",
        es: "Comience por editar",
      }),
      pageLink: "src/app/page.tsx",
    },
  },
};

export default pageContent;
```

```javascript fileName="src/app/[locale]/page.content.cjs" contentDeclarationFormat="commonjs"
const { t } = require("intlayer");

/** @type {import('intlayer').Dictionary} */
const pageContent = {
  key: "page",
  content: {
    getStarted: {
      main: t({
        "en-GB": "Get started by editing",
        en: "Get started by editing",
        fr: "Commencez par éditer",
        es: "Comience por editar",
      }),
      pageLink: "src/app/page.tsx",
    },
  },
};

module.exports = pageContent;
```

```json fileName="src/app/[locale]/page.content.json" contentDeclarationFormat="json"
{
  "$schema": "https://intlayer.org/schema.json",
  "key": "page",
  "content": {
    "getStarted": {
      "nodeType": "translation",
      "translation": {
        "en-GB": "Get started by editing",
        "en": "Get started by editing",
        "fr": "Commencez par éditer",
        "es": "Comience por editar"
      }
    },
    "pageLink": "src/app/page.tsx"
  }
}
```

> Your content declarations can be defined anywhere in your application as soon as they are included in the `contentDir` directory (by default, `./src`). And match the content declaration file extension (by default, `.content.{json,ts,tsx,js,jsx,mjs,cjs}`).

> For more details, refer to the [content declaration documentation](https://github.com/aymericzip/intlayer/blob/main/docs/docs/en-GB/dictionary/content_file.md).

### Step 6: Utilise Content in Your Code

Access your content dictionaries throughout your application:

```tsx fileName="src/app/[locale]/page.tsx" codeFormat="typescript"
import type { FC } from "react";
import { ClientComponentExample } from "@components/ClientComponentExample";
import { ServerComponentExample } from "@components/ServerComponentExample";
import { type NextPageIntlayer, IntlayerClientProvider } from "next-intlayer";
import { IntlayerServerProvider, useIntlayer } from "next-intlayer/server";

const PageContent: FC = () => {
  const content = useIntlayer("page");

  return (
    <>
      <p>{content.getStarted.main}</p>
      <code>{content.getStarted.pageLink}</code>
    </>
  );
};

const Page: NextPageIntlayer = async ({ params }) => {
  const { locale } = await params;

  return (
    <IntlayerServerProvider locale={locale}>
      <PageContent />
      <ServerComponentExample />

      <IntlayerClientProvider locale={locale}>
        <ClientComponentExample />
      </IntlayerClientProvider>
    </IntlayerServerProvider>
  );
};

export default Page;
```

```jsx fileName="src/app/[locale]/page.mjx" codeFormat="esm"
import { ClientComponentExample } from "@components/ClientComponentExample";
import { ServerComponentExample } from "@components/ServerComponentExample";
import { IntlayerClientProvider } from "next-intlayer";
import { IntlayerServerProvider, useIntlayer } from "next-intlayer/server";

const PageContent = () => {
  const content = useIntlayer("page");

  return (
    <>
      <p>{content.getStarted.main}</p>
      <code>{content.getStarted.pageLink}</code>
    </>
  );
};

const Page = async ({ params }) => {
  const { locale } = await params;

  return (
    <IntlayerServerProvider locale={locale}>
      <PageContent />
      <ServerComponentExample />

      <IntlayerClientProvider locale={locale}>
        <ClientComponentExample />
      </IntlayerClientProvider>
    </IntlayerServerProvider>
  );
};

export default Page;
```

```jsx fileName="src/app/[locale]/page.csx" codeFormat="commonjs"
import { ClientComponentExample } from "@components/ClientComponentExample";
import { ServerComponentExample } from "@components/ServerComponentExample";
import { IntlayerClientProvider } from "next-intlayer";
import { IntlayerServerProvider, useIntlayer } from "next-intlayer/server";

const PageContent = () => {
  const content = useIntlayer("page");

  return (
    <>
      <p>{content.getStarted.main}</p>
      <code>{content.getStarted.pageLink}</code>
    </>
  );
};

const Page = async ({ params }) => {
  const { locale } = await params;

  return (
    <IntlayerServerProvider locale={locale}>
      <PageContent />
      <ServerComponentExample />

      <IntlayerClientProvider locale={locale}>
        <ClientComponentExample />
      </IntlayerClientProvider>
    </IntlayerServerProvider>
  );
};
```

- **`IntlayerClientProvider`** is used to provide the locale to client-side components. It can be placed in any parent component, including the layout. However, placing it in a layout is recommended because Next.js shares layout code across pages, making it more efficient. By using `IntlayerClientProvider` in the layout, you avoid reinitialising it for every page, improving performance and maintaining a consistent localisation context throughout your application.
- **`IntlayerServerProvider`** is used to provide the locale to the server children. It cannot be set in the layout.

  > Layout and page cannot share a common server context because the server context system is based on a per-request data store (via [React's cache](https://react.dev/reference/react/cache) mechanism), causing each "context" to be re-created for different segments of the application. Placing the provider in a shared layout would break this isolation, preventing the correct propagation of the server context values to your server components.

  > Layout and page cannot share a common server context because the server context system is based on a per-request data store (via [React's cache](https://react.dev/reference/react/cache) mechanism), causing each "context" to be re-created for different segments of the application. Placing the provider in a shared layout would break this isolation, preventing the correct propagation of the server context values to your server components.

```tsx {4,7} fileName="src/components/ClientComponentExample.tsx" codeFormat="typescript"
"use client";

import type { FC } from "react";
import { useIntlayer } from "next-intlayer";

export const ClientComponentExample: FC = () => {
  const content = useIntlayer("client-component-example"); // Create related content declaration

  return (
    <div>
      <h2>{content.title}</h2>
      <p>{content.content}</p>
    </div>
  );
};
```

```jsx {3,6} fileName="src/components/ClientComponentExample.mjx" codeFormat="esm"
"use client";

import { useIntlayer } from "next-intlayer";

const ClientComponentExample = () => {
  const content = useIntlayer("client-component-example"); // Create related content declaration

  return (
    <div>
      <h2>{content.title}</h2>
      <p>{content.content}</p>
    </div>
  );
};
```

```jsx {3,6} fileName="src/components/ClientComponentExample.csx" codeFormat="commonjs"
"use client";

const { useIntlayer } = require("next-intlayer");

const ClientComponentExample = () => {
  const content = useIntlayer("client-component-example"); // Create related content declaration

  return (
    <div>
      <h2>{content.title}</h2>
      <p>{content.content}</p>
    </div>
  );
};
```

```tsx {2} fileName="src/components/ServerComponentExample.tsx"  codeFormat="typescript"
import type { FC } from "react";
import { useIntlayer } from "next-intlayer/server";

export const ServerComponentExample: FC = () => {
  const content = useIntlayer("server-component-example"); // Create related content declaration

  return (
    <div>
      <h2>{content.title}</h2>
      <p>{content.content}</p>
    </div>
  );
};
```

```jsx {1} fileName="src/components/ServerComponentExample.mjx" codeFormat="esm"
import { useIntlayer } from "next-intlayer/server";

const ServerComponentExample = () => {
  const content = useIntlayer("server-component-example"); // Create related content declaration

  return (
    <div>
      <h2>{content.title}</h2>
      <p>{content.content}</p>
    </div>
  );
};
```

```jsx {1} fileName="src/components/ServerComponentExample.csx" codeFormat="commonjs"
const { useIntlayer } = require("next-intlayer/server");

const ServerComponentExample = () => {
  const content = useIntlayer("server-component-example"); // Create related content declaration

  return (
    <div>
      <h2>{content.title}</h2>
      <p>{content.content}</p>
    </div>
  );
};
```

> If you want to use your content in a `string` attribute, such as `alt`, `title`, `href`, `aria-label`, etc., you must call the value of the function, like:

> ```jsx
> <img src={content.image.src.value} alt={content.image.value} />
> ```

> To learn more about the `useIntlayer` hook, refer to the [documentation](https://github.com/aymericzip/intlayer/blob/main/docs/docs/en-GB/packages/next-intlayer/useIntlayer.md).

### (Optional) Step 7: Configure Middleware for Locale Detection

Set up middleware to detect the user's preferred locale:

```typescript fileName="src/middleware.ts" codeFormat="typescript"
export { intlayerMiddleware as middleware } from "next-intlayer/middleware";

export const config = {
  matcher:
    "/((?!api|static|assets|robots|sitemap|sw|service-worker|manifest|.*\\..*|_next).*)",
};
```

```javascript fileName="src/middleware.mjs" codeFormat="esm"
export { intlayerMiddleware as middleware } from "next-intlayer/middleware";

export const config = {
  matcher:
    "/((?!api|static|assets|robots|sitemap|sw|service-worker|manifest|.*\\..*|_next).*)",
};
```

```javascript fileName="src/middleware.cjs" codeFormat="commonjs"
const { intlayerMiddleware } = require("next-intlayer/middleware");

const config = {
  matcher:
    "/((?!api|static|assets|robots|sitemap|sw|service-worker|manifest|.*\\..*|_next).*)",
};

module.exports = { middleware: intlayerMiddleware, config };
```

> The `intlayerMiddleware` is used to detect the user's preferred locale and redirect them to the appropriate URL as specified in the [configuration](https://github.com/aymericzip/intlayer/blob/main/docs/docs/en-GB/configuration.md). Additionally, it enables saving the user's preferred locale in a cookie.

### (Optional) Step 8: Internationalisation of your metadata

In the case you want to internationalise your metadata, such as the title of your page, you can use the `generateMetadata` function provided by Next.js. Inside, you can retrieve the content from the `getIntlayer` function to translate your metadata.

```typescript fileName="src/app/[locale]/metadata.content.ts" contentDeclarationFormat="typescript"
import { type Dictionary, t } from "intlayer";
import { Metadata } from "next";

const metadataContent = {
  key: "page-metadata",
  content: {
    title: t({
      en: "Create Next App",
      fr: "Créer une application Next.js",
      es: "Crear una aplicación Next.js",
    }),
    description: t({
      en: "Generated by create next app",
      fr: "Généré par create next app",
      es: "Generado por create next app",
    }),
  },
} satisfies Dictionary<Metadata>;

export default metadataContent;
```

```javascript fileName="src/app/[locale]/metadata.content.mjs" contentDeclarationFormat="esm"
import { t } from "intlayer";

/** @type {import('intlayer').Dictionary<import('next').Metadata>} */
const metadataContent = {
  key: "page-metadata",
  content: {
    title: t({
      en: "Create Next App",
      fr: "Créer une application Next.js",
      es: "Crear una aplicación Next.js",
    }),
    description: t({
      en: "Generated by create next app",
      fr: "Généré par create next app",
      es: "Generado por create next app",
    }),
  },
};

export default metadataContent;
```

```javascript fileName="src/app/[locale]/metadata.content.cjs" contentDeclarationFormat="commonjs"
const { t } = require("intlayer");
/** @type {import('intlayer').Dictionary<import('next').Metadata>} */
const metadataContent = {
  key: "page-metadata",
  content: {
    title: t({
      en: "Create Next App",
      fr: "Créer une application Next.js",
      es: "Crear una aplicación Next.js",
    }),
    description: t({
      en: "Generated by create next app",
      fr: "Généré par create next app",
      es: "Generado por create next app",
    }),
  },
};

module.exports = metadataContent;

/** @type {import('intlayer').Dictionary<import('next').Metadata>} */
const metadataContent = {
  key: "page-metadata",
  content: {
    title: t({
      "en-GB": "Create Next App",
      en: "Create Next App",
      fr: "Créer une application Next.js",
      es: "Crear una aplicación Next.js",
    }),
    description: t({
      "en-GB": "Generated by create next app",
      en: "Generated by create next app",
      fr: "Généré par create next app",
      es: "Generado por create next app",
    }),
  },
};

module.exports = metadataContent;
```

```json fileName="src/app/[locale]/metadata.content.json" contentDeclarationFormat="json"
{
  "key": "page-metadata",
  "content": {
    "title": {
      "nodeType": "translation",
      "translation": {
          "en-GB": "Preact logo",
          "en": "Preact logo",
          "fr": "Logo Preact",
          "es": "Logo Preact",
      },
    },
    "description": {
      "nodeType": "translation",
      "translation": {
        "en-GB": "Generated by create next app",
        "en": "Generated by create next app",
        "fr": "Généré par create next app",
        "es": "Generado por create next app",
      },
    },
  },
};
```

````typescript fileName="src/app/[locale]/layout.tsx or src/app/[locale]/page.tsx" codeFormat="typescript"
import { getIntlayer, getMultilingualUrls } from "intlayer";
import type { Metadata } from "next";
import type { LocalPromiseParams } from "next-intlayer";

export const generateMetadata = async ({
  params,
}: LocalPromiseParams): Promise<Metadata> => {
  const { locale } = await params;

  const metadata = getIntlayer("page-metadata", locale);

  /**
   * Generates an object containing all URLs for each locale.
   *
   * Example:
   * ```ts
   *  getMultilingualUrls('/about');
   *
   *  // Returns
   *  // {
   *  //   en: '/about',
   *  //   fr: '/fr/about',
   *  //   es: '/es/about',
   *  // }
   * ```
   */
  const multilingualUrls = getMultilingualUrls("/");
  const localizedUrl =
    multilingualUrls[locale as keyof typeof multilingualUrls];

  return {
    ...metadata,
    alternates: {
      canonical: localizedUrl,
      languages: { ...multilingualUrls, "x-default": "/" },
    },
    openGraph: {
      url: localizedUrl,
    },
  };
};

// ... Rest of the code
````

````javascript fileName="src/app/[locale]/layout.mjs or src/app/[locale]/page.mjs" codeFormat="esm"
import { getIntlayer, getMultilingualUrls } from "intlayer";

export const generateMetadata = async ({ params }) => {
  const { locale } = await params;

  const metadata = getIntlayer("page-metadata", locale);

  /**
   * Generates an object containing all URLs for each locale.
   *
   * Example:
   * ```ts
   *  getMultilingualUrls('/about');
   *
   *  // Returns
   *  // {
   *  //   en: '/about',
   *  //   fr: '/fr/about',
   *  //   es: '/es/about'
   *  // }
   * ```
   */
  const multilingualUrls = getMultilingualUrls("/");
  const localizedUrl = multilingualUrls[locale];

  return {
    ...metadata,
    alternates: {
      canonical: localizedUrl,
      languages: { ...multilingualUrls, "x-default": "/" },
    },
    openGraph: {
      url: localizedUrl,
    },
  };
};

// ... Rest of the code
````

````javascript fileName="src/app/[locale]/layout.cjs or src/app/[locale]/page.cjs" codeFormat="commonjs"
const { getIntlayer, getMultilingualUrls } = require("intlayer");

const generateMetadata = async ({ params }) => {
  const { locale } = await params;

  const metadata = getIntlayer("page-metadata", locale);

  /**
   * Generates an object containing all URLs for each locale.
   *
   * Example:
   * ```ts
   *  getMultilingualUrls('/about');
   *
   *  // Returns
   *  // {
   *  //   en: '/about',
   *  //   fr: '/fr/about',
   *  //   es: '/es/about'
   *  // }
   * ```
   */
  const multilingualUrls = getMultilingualUrls("/");
  const localizedUrl = multilingualUrls[locale];

  return {
    ...metadata,
    alternates: {
      canonical: localizedUrl,
      languages: { ...multilingualUrls, "x-default": "/" },
    },
    openGraph: {
      url: localizedUrl,
    },
  };
};

module.exports = { generateMetadata };

// ... Rest of the code
````

> Note that the `getIntlayer` function imported from `next-intlayer` returns your content wrapped in an `IntlayerNode`, allowing integration with the visual editor. In contrast, the `getIntlayer` function imported from `intlayer` returns your content directly without additional properties.

Alternatively, you can use the `getTranslation` function to declare your metadata. However, using content declaration files is recommended to automate the translation of your metadata and externalise the content at some point.

```typescript fileName="src/app/[locale]/layout.tsx or src/app/[locale]/page.tsx" codeFormat="typescript"
import {
  type IConfigLocales,
  getTranslation,
  getMultilingualUrls,
} from "intlayer";
import type { Metadata } from "next";
import type { LocalPromiseParams } from "next-intlayer";

export const generateMetadata = async ({
  params,
}: LocalPromiseParams): Promise<Metadata> => {
  const { locale } = await params;
  const t = <T>(content: IConfigLocales<T>) => getTranslation(content, locale);

  return {
    title: t<string>({
      en: "My title",
      fr: "Mon titre",
      es: "Mi título",
    }),
    description: t({
      en: "My description",
      fr: "Ma description",
      es: "Mi descripción",
    }),
  };
};

// ... Rest of the code
```

```javascript fileName="src/app/[locale]/layout.mjs or src/app/[locale]/page.mjs" codeFormat="esm"
import { getTranslation, getMultilingualUrls } from "intlayer";

export const generateMetadata = async ({ params }) => {
  const { locale } = await params;
  const t = (content) => getTranslation(content, locale);

  return {
    title: t({
      en: "My title",
      fr: "Mon titre",
      es: "Mi título",
    }),
    description: t({
      en: "My description",
      fr: "Ma description",
      es: "Mi descripción",
    }),
  };
};

// ... Rest of the code
```

```javascript fileName="src/app/[locale]/layout.cjs or src/app/[locale]/page.cjs" codeFormat="commonjs"
const { getTranslation, getMultilingualUrls } = require("intlayer");

const generateMetadata = async ({ params }) => {
  const { locale } = await params;

  const t = (content) => getTranslation(content, locale);

  return {
    title: t({
      en: "My title",
      fr: "Mon titre",
      es: "Mi título",
    }),
    description: t({
      en: "My description",
      fr: "Ma description",
      es: "Mi descripción",
    }),
  };
};

module.exports = { generateMetadata };

// ... Rest of the code
```

> Learn more about metadata optimisation [on the official Next.js documentation](https://nextjs.org/docs/app/building-your-application/optimizing/metadata).

### (Optional) Step 9: Internationalisation of your sitemap.xml and robots.txt

To internationalise your `sitemap.xml` and `robots.txt`, you can use the `getMultilingualUrls` function provided by Intlayer. This function allows you to generate multilingual URLs for your sitemap.

```tsx fileName="src/app/sitemap.ts" codeFormat="typescript"
import { getMultilingualUrls } from "intlayer";
import type { MetadataRoute } from "next";

const sitemap = (): MetadataRoute.Sitemap => [
  {
    url: "https://example.com",
    alternates: {
      languages: {
        ...getMultilingualUrls("https://example.com"),
        "x-default": "https://example.com",
      },
    },
  },
  {
    url: "https://example.com/login",
    alternates: {
      languages: {
        ...getMultilingualUrls("https://example.com/login"),
        "x-default": "https://example.com/login",
      },
    },
  },
  {
    url: "https://example.com/register",
    alternates: {
      languages: {
        ...getMultilingualUrls("https://example.com/register"),
        "x-default": "https://example.com/register",
      },
    },
  },
];

export default sitemap;
```

```jsx fileName="src/app/sitemap.mjx" codeFormat="esm"
import { getMultilingualUrls } from "intlayer";

const sitemap = () => [
  {
    url: "https://example.com",
    alternates: {
      languages: {
        ...getMultilingualUrls("https://example.com"),
        "x-default": "https://example.com",
      },
    },
  },
  {
    url: "https://example.com/login",
    alternates: {
      languages: {
        ...getMultilingualUrls("https://example.com/login"),
        "x-default": "https://example.com/login",
      },
    },
  },
  {
    url: "https://example.com/register",
    alternates: {
      languages: {
        ...getMultilingualUrls("https://example.com/register"),
        "x-default": "https://example.com/register",
      },
    },
  },
];

export default sitemap;
```

```jsx fileName="src/app/sitemap.csx" codeFormat="commonjs"
const { getMultilingualUrls } = require("intlayer");

const sitemap = () => [
  {
    url: "https://example.com",
    alternates: {
      languages: {
        ...getMultilingualUrls("https://example.com"),
        "x-default": "https://example.com",
      },
    },
  },
  {
    url: "https://example.com/login",
    alternates: {
      languages: {
        ...getMultilingualUrls("https://example.com/login"),
        "x-default": "https://example.com/login",
      },
    },
  },
  {
    url: "https://example.com/register",
    alternates: {
      languages: {
        ...getMultilingualUrls("https://example.com/register"),
        "x-default": "https://example.com/register",
      },
    },
  },
];

module.exports = sitemap;
```

```tsx fileName="src/app/robots.ts" codeFormat="typescript"
import type { MetadataRoute } from "next";
import { getMultilingualUrls } from "intlayer";

const getAllMultilingualUrls = (urls: string[]) =>
  urls.flatMap((url) => Object.values(getMultilingualUrls(url)) as string[]);

// Robots.txt configuration for search engine crawlers
const robots = (): MetadataRoute.Robots => ({
  rules: {
    userAgent: "*",
    allow: ["/"],
    disallow: getAllMultilingualUrls(["/login", "/register"]), // Disallow login and register pages
  },
  host: "https://example.com",
  sitemap: `https://example.com/sitemap.xml`,
});

export default robots;
```

```jsx fileName="src/app/robots.mjx" codeFormat="esm"
import { getMultilingualUrls } from "intlayer";

const getAllMultilingualUrls = (urls) =>
  urls.flatMap((url) => Object.values(getMultilingualUrls(url)));

const robots = () => ({
  rules: {
    userAgent: "*",
    allow: ["/"],
    disallow: getAllMultilingualUrls(["/login", "/register"]),
  },
  host: "https://example.com",
  sitemap: `https://example.com/sitemap.xml`,
});

export default robots;
```

```jsx fileName="src/app/robots.csx" codeFormat="commonjs"
const { getMultilingualUrls } = require("intlayer");

const getAllMultilingualUrls = (urls) =>
  urls.flatMap((url) => Object.values(getMultilingualUrls(url)));

const robots = () => ({
  rules: {
    userAgent: "*",
    allow: ["/"],
    disallow: getAllMultilingualUrls(["/login", "/register"]),
  },
  host: "https://example.com",
  sitemap: `https://example.com/sitemap.xml`,
});

module.exports = robots;
```

> Learn more about sitemap optimisation [on the official Next.js documentation](https://nextjs.org/docs/app/api-reference/file-conventions/metadata/sitemap). Learn more about robots.txt optimisation [on the official Next.js documentation](https://nextjs.org/docs/app/api-reference/file-conventions/metadata/robots).

### (Optional) Step 10: Change the language of your content

To change the language of your content in Next.js, the recommended method is to use the `Link` component to redirect users to the appropriate localised page. The `Link` component enables prefetching of the page, which helps avoid a full page reload.

```tsx fileName="src/components/LocaleSwitcher.tsx" codeFormat="typescript"
"use client";

import type { FC } from "react";
import {
  Locales,
  getHTMLTextDir,
  getLocaleName,
  getLocalizedUrl,
} from "intlayer";
import { useLocale } from "next-intlayer";
import Link from "next/link";

export const LocaleSwitcher: FC = () => {
  const { locale, pathWithoutLocale, availableLocales, setLocale } =
    useLocale();

  return (
    <div>
      <button popoverTarget="localePopover">{getLocaleName(locale)}</button>
      <div id="localePopover" popover="auto">
        {availableLocales.map((localeItem) => (
          <Link
            href={getLocalizedUrl(pathWithoutLocale, localeItem)}
            hrefLang={localeItem}
            key={localeItem}
            aria-current={locale === localeItem ? "page" : undefined}
            onClick={() => setLocale(localeItem)}
          >
            <span>
              {/* Locale - e.g. FR */}
              {localeItem}
            </span>
            <span>
              {/* Language in its own Locale - e.g. Français */}
              {getLocaleName(localeItem, locale)}
            </span>
            <span dir={getHTMLTextDir(localeItem)} lang={localeItem}>
              {/* Language in current Locale - e.g. Francés with current locale set to Locales.SPANISH */}
              {getLocaleName(localeItem)}
            </span>
            <span dir="ltr" lang={Locales.ENGLISH}>
              {/* Language in English - e.g. French */}
              {getLocaleName(localeItem, Locales.ENGLISH)}
            </span>
          </Link>
        ))}
      </div>
    </div>
  );
};
```

```jsx fileName="src/components/LocaleSwitcher.msx" codeFormat="esm"
"use client";

import {
  Locales,
  getHTMLTextDir,
  getLocaleName,
  getLocalizedUrl,
} from "intlayer";
import { useLocale } from "next-intlayer";
import Link from "next/link";

export const LocaleSwitcher = () => {
  const { locale, pathWithoutLocale, availableLocales, setLocale } =
    useLocale();

  return (
    <div>
      <button popoverTarget="localePopover">{getLocaleName(locale)}</button>
      <div id="localePopover" popover="auto">
        {availableLocales.map((localeItem) => (
          <Link
            href={getLocalizedUrl(pathWithoutLocale, localeItem)}
            hrefLang={localeItem}
            key={localeItem}
            aria-current={locale === localeItem ? "page" : undefined}
            onClick={() => setLocale(localeItem)}
          >
            <span>
              {/* Locale - e.g. FR */}
              {localeItem}
            </span>
            <span>
              {/* Language in its own Locale - e.g. Français */}
              {getLocaleName(localeItem, locale)}
            </span>
            <span dir={getHTMLTextDir(localeItem)} lang={localeItem}>
              {/* Language in current Locale - e.g. Francés with current locale set to Locales.SPANISH */}
              {getLocaleName(localeItem)}
            </span>
            <span dir="ltr" lang={Locales.ENGLISH}>
              {/* Language in English - e.g. French */}
              {getLocaleName(localeItem, Locales.ENGLISH)}
            </span>
          </Link>
        ))}
      </div>
    </div>
  );
};
```

```jsx fileName="src/components/LocaleSwitcher.csx" codeFormat="commonjs"
"use client";

const {
  Locales,
  getHTMLTextDir,
  getLocaleName,
  getLocalizedUrl,
} = require("intlayer");
const { useLocale } = require("next-intlayer");
const Link = require("next/link");

export const LocaleSwitcher = () => {
  const { locale, pathWithoutLocale, availableLocales, setLocale } =
    useLocale();

  return (
    <div>
      <button popoverTarget="localePopover">{getLocaleName(locale)}</button>
      <div id="localePopover" popover="auto">
        {availableLocales.map((localeItem) => (
          <Link
            href={getLocalizedUrl(pathWithoutLocale, localeItem)}
            hrefLang={localeItem}
            key={localeItem}
            aria-current={locale === localeItem ? "page" : undefined}
            onClick={() => setLocale(localeItem)}
          >
            <span>
              {/* Locale - e.g. FR */}
              {localeItem}
            </span>
            <span>
              {/* Language in its own Locale - e.g. Français */}
              {getLocaleName(localeItem, locale)}
            </span>
            <span dir={getHTMLTextDir(localeItem)} lang={localeItem}>
              {/* Language in current Locale - e.g. Francés with current locale set to Locales.SPANISH */}
              {getLocaleName(localeItem)}
            </span>
            <span dir="ltr" lang={Locales.ENGLISH}>
              {/* Language in English - e.g. French */}
              {getLocaleName(localeItem, Locales.ENGLISH)}
            </span>
          </Link>
        ))}
      </div>
    </div>
  );
};
```

> An alternative method is to use the `setLocale` function provided by the `useLocale` hook. This function will not permit prefetching the page and will reload the page.

> In this case, without redirection using `router.push`, only your server-side code will modify the locale of the content.

```tsx fileName="src/components/LocaleSwitcher.tsx" codeFormat="typescript"
"use client";

import { useRouter } from "next/navigation";
import { useLocale } from "next-intlayer";
import { getLocalizedUrl } from "intlayer";

// ... Rest of the code

const router = useRouter();
const { setLocale } = useLocale({
  onLocaleChange: (locale) => {
    router.push(getLocalizedUrl(pathWithoutLocale, locale));
  },
});

return (
  <button onClick={() => setLocale(Locales.FRENCH)}>Change to French</button>
);
```

> Documentation references:
>
> - [`useLocale` hook](https://github.com/aymericzip/intlayer/blob/main/docs/docs/en-GB/packages/next-intlayer/useLocale.md)
> - [`getLocaleName` hook](https://github.com/aymericzip/intlayer/blob/main/docs/docs/en-GB/packages/intlayer/getLocaleName.md)
> - [`getLocalizedUrl` hook](https://github.com/aymericzip/intlayer/blob/main/docs/docs/en-GB/packages/intlayer/getLocalizedUrl.md)
> - [`getHTMLTextDir` hook](https://github.com/aymericzip/intlayer/blob/main/docs/docs/en-GB/packages/intlayer/getHTMLTextDir.md)
> - [`hrefLang` attribute](https://developers.google.com/search/docs/specialty/international/localized-versions?hl=fr)
> - [`lang` attribute](https://developer.mozilla.org/en-US/docs/Web/HTML/Global_attributes/lang)
> - [`dir` attribute](https://developer.mozilla.org/en-US/docs/Web/HTML/Global_attributes/dir)
> - [`aria-current` attribute](https://developer.mozilla.org/en-US/docs/Web/Accessibility/ARIA/Attributes/aria-current)

### (Optional) Step 11: Creating a Localised Link Component

To ensure that your application's navigation respects the current locale, you can create a custom `Link` component. This component automatically prefixes internal URLs with the current language. For example, when a French-speaking user clicks on a link to the "About" page, they are redirected to `/fr/about` instead of `/about`.

This behaviour is useful for several reasons:

- **SEO and User Experience**: Localised URLs help search engines index language-specific pages correctly and provide users with content in their preferred language.
- **Consistency**: By using a localised link throughout your application, you guarantee that navigation stays within the current locale, preventing unexpected language switches.
- **Maintainability**: Centralising the localisation logic in a single component simplifies the management of URLs, making your codebase easier to maintain and extend as your application grows.

Below is the implementation of a localised `Link` component in TypeScript:

```tsx fileName="src/components/Link.tsx" codeFormat="typescript"
"use client";

import { getLocalizedUrl } from "intlayer";
import NextLink, { type LinkProps as NextLinkProps } from "next/link";
import { useLocale } from "next-intlayer";
import type { PropsWithChildren, FC } from "react";

/**
 * Utility function to check whether a given URL is external.
 * If the URL starts with http:// or https://, it is considered external.
 */
export const checkIsExternalLink = (href?: string): boolean =>
  /^https?:\/\//.test(href ?? "");

/**
 * A custom Link component that adapts the href attribute based on the current locale.
 * For internal links, it uses `getLocalizedUrl` to prefix the URL with the locale (e.g., /fr/about).
 * This ensures that navigation remains within the same locale context.
 */
export const Link: FC<PropsWithChildren<NextLinkProps>> = ({
  href,
  children,
  ...props
}) => {
  const { locale } = useLocale();
  const isExternalLink = checkIsExternalLink(href.toString());

  // If the link is internal and a valid href is provided, get the localised URL.
  const hrefI18n: NextLinkProps["href"] =
    href && !isExternalLink ? getLocalizedUrl(href.toString(), locale) : href;

  return (
    <NextLink href={hrefI18n} {...props}>
      {children}
    </NextLink>
  );
};
```

```jsx fileName="src/components/Link.mjx" codeFormat="esm"
"use client";

import { getLocalizedUrl } from "intlayer";
import NextLink from "next/link";
import { useLocale } from "next-intlayer";

/**
 * Utility function to check whether a given URL is external.
 * If the URL starts with http:// or https://, it is considered external.
 */
export const checkIsExternalLink = (href) => /^https?:\/\//.test(href ?? "");

/**
 * A custom Link component that adapts the href attribute based on the current locale.
 * For internal links, it uses `getLocalizedUrl` to prefix the URL with the locale (e.g., /fr/about).
 * This ensures that navigation stays within the same locale context.
 */
export const Link = ({ href, children, ...props }) => {
  const { locale } = useLocale();
  const isExternalLink = checkIsExternalLink(href.toString());

  // If the link is internal and a valid href is provided, get the localised URL.
  const hrefI18n =
    href && !isExternalLink ? getLocalizedUrl(href.toString(), locale) : href;

  return (
    <NextLink href={hrefI18n} {...props}>
      {children}
    </NextLink>
  );
};
```

```jsx fileName="src/components/Link.csx" codeFormat="commonjs"
"use client";

const { getLocalizedUrl } = require("intlayer");
const NextLink = require("next/link");
const { useLocale } = require("next-intlayer");

/**
 * Utility function to check whether a given URL is external.
 * If the URL starts with http:// or https://, it is considered external.
 */
const checkIsExternalLink = (href) => /^https?:\/\//.test(href ?? "");

/**
 * A custom Link component that adapts the href attribute based on the current locale.
 * For internal links, it uses `getLocalizedUrl` to prefix the URL with the locale (e.g., /fr/about).
 * This ensures that navigation remains within the same locale context.
 */
const Link = ({ href, children, ...props }) => {
  const { locale } = useLocale();
  const isExternalLink = checkIsExternalLink(href.toString());

  // If the link is internal and a valid href is provided, get the localised URL.
  const hrefI18n =
    href && !isExternalLink ? getLocalizedUrl(href.toString(), locale) : href;

  return (
    <NextLink href={hrefI18n} {...props}>
      {children}
    </NextLink>
  );
};
```

#### How It Works

- **Detecting External Links**:  
  The helper function `checkIsExternalLink` determines whether a URL is external. External links are left unchanged because they do not need localisation.

- **Retrieving the Current Locale**:  
  The `useLocale` hook provides the current locale (e.g., `fr` for French).

- **Localising the URL**:  
  For internal links (i.e., non-external), `getLocalizedUrl` is used to automatically prefix the URL with the current locale. This means that if your user is in French, passing `/about` as the `href` will transform it to `/fr/about`.

- **Returning the Link**:  
  The component returns an `<a>` element with the localised URL, ensuring that navigation is consistent with the locale.

By integrating this `Link` component across your application, you maintain a coherent and language-aware user experience while also benefiting from improved SEO and usability.

### (Optional) Step 12: Optimise your bundle size

When using `next-intlayer`, dictionaries are included in the bundle for every page by default. To optimise bundle size, Intlayer provides an optional SWC plugin that intelligently replaces `useIntlayer` calls using macros. This ensures dictionaries are only included in bundles for pages that actually use them.

To enable this optimisation, install the `@intlayer/swc` package. Once installed, `next-intlayer` will automatically detect and use the plugin:

```bash packageManager="npm"
npm install @intlayer/swc --save-dev
```

```bash packageManager="pnpm"
pnpm add @intlayer/swc --save-dev
```

```bash packageManager="yarn"
yarn add @intlayer/swc --save-dev
```

```bash packageManager="bun"
bun add @intlayer/swc --dev
```

> Note: This optimisation is only available for Next.js 13 and above.

> Note: This package is not installed by default because SWC plugins are still experimental on Next.js. It may change in the future.

### Configure TypeScript

Intlayer uses module augmentation to benefit from TypeScript and make your codebase stronger.

![Autocompletion](https://github.com/aymericzip/intlayer/blob/main/docs/assets/autocompletion.png?raw=true)

![Translation error](https://github.com/aymericzip/intlayer/blob/main/docs/assets/translation_error.png?raw=true)

Ensure your TypeScript configuration includes the autogenerated types.

```json5 fileName="tsconfig.json"
{
  // ... Your existing TypeScript configurations
  "include": [
    // ... Your existing TypeScript configurations
    ".intlayer/**/*.ts", // Include the auto-generated types
  ],
}
```

### Git Configuration

It is recommended to ignore the files generated by Intlayer. This prevents you from committing them to your Git repository.

To do this, you can add the following instructions to your `.gitignore` file:

```plaintext fileName=".gitignore"
# Ignore the files generated by Intlayer
.intlayer
```

### VS Code Extension

To enhance your development experience with Intlayer, you can install the official **Intlayer VS Code Extension**.

[Install from the VS Code Marketplace](https://marketplace.visualstudio.com/items?itemName=intlayer.intlayer-vs-code-extension)

This extension provides:

- **Autocompletion** for translation keys.
- **Real-time error detection** for missing translations.
- **Inline previews** of translated content.
- **Quick actions** to easily create and update translations.

For more details on how to use the extension, refer to the [Intlayer VS Code Extension documentation](https://intlayer.org/doc/vs-code-extension).

### Go Further

To go further, you can implement the [visual editor](https://github.com/aymericzip/intlayer/blob/main/docs/docs/en-GB/intlayer_visual_editor.md) or externalise your content using the [CMS](https://github.com/aymericzip/intlayer/blob/main/docs/docs/en-GB/intlayer_CMS.md).
