---
createdAt: 2024-03-07
updatedAt: 2025-10-03
title: How to translate your Astro app – i18n guide 2025
description: Learn how to add internationalization (i18n) to your Vite and React application using Intlayer. Follow this guide to make your app multilingual.
keywords:
  - Internationalization
  - Documentation
  - Intlayer
  - Vite
  - React
  - i18n
  - JavaScript
slugs:
  - doc
  - environment
  - astro
applicationTemplate: https://github.com/aymericzip/intlayer-astro-template
history:
  - version: 6.2.0
    date: 2025-10-03
    changes: Refresh for Astro integration, config, usage
---

# Translate your Astro website using Intlayer | Internationalization (i18n)

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

## What is Intlayer?

**Intlayer** is an innovative, open-source internationalization (i18n) library designed to simplify multilingual support in modern web applications.

With Intlayer, you can:

- **Easily manage translations** using declarative dictionaries at the component level.
- **Dynamically localize metadata**, routes, and content.
- **Ensure TypeScript support** with autogenerated types, improving autocompletion and error detection.
- **Benefit from advanced features**, like dynamic locale detection and switching.

---

## Step-by-Step Guide to Set Up Intlayer in Astro

### Step 1: Install Dependencies

Install the necessary packages using your package manager:

```bash packageManager="npm"
npm install intlayer astro-intlayer
# Optional: add React island support
npm install react react-dom react-intlayer @astrojs/react
```

```bash packageManager="pnpm"
pnpm add intlayer astro-intlayer
# Optional: add React island support
pnpm add react react-dom react-intlayer @astrojs/react
```

```bash packageManager="yarn"
yarn add intlayer astro-intlayer
# Optional: add React island support
yarn add react react-dom react-intlayer @astrojs/react
```

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

- **astro-intlayer**
  Includes the Astro integration plugin for integrating Intlayer with the [Vite bundler](https://vite.dev/guide/why.html#why-bundle-for-production), as well as middleware for detecting the user's preferred locale, managing cookies, and handling URL redirection.

### Step 2: Configuration of your project

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

```typescript fileName="intlayer.config.ts"
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;
```

> Through this configuration file, you can set up localized 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/configuration.md).

### Step 3: Integrate Intlayer in Your Astro Configuration

Add the intlayer plugin into your configuration.

```typescript fileName="astro.config.ts"
// @ts-check

import { intlayer } from "astro-intlayer";
import { defineConfig } from "astro/config";

// https://astro.build/config
export default defineConfig({
  integrations: [intlayer()],
});
```

> The `intlayer()` Astro integration plugin is used to integrate Intlayer with Astro. It ensures the building of content declaration files and monitors them in development mode. It defines Intlayer environment variables within the Astro application. Additionally, it provides aliases to optimize performance.

### Step 4: Declare Your Content

Create and manage your content declarations to store translations:

```tsx fileName="src/app.content.tsx"
import { t, type Dictionary } from "intlayer";
import type { ReactNode } from "react";

const appContent = {
  key: "app",
  content: {
    title: t({
      en: "Hello World",
      fr: "Bonjour le monde",
      es: "Hola mundo",
    }),
  },
} satisfies Dictionary;

export default appContent;
```

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

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

### Step 5: Use your content in Astro

You can consume dictionaries directly in `.astro` files using the core helpers exported by `intlayer`.

```astro fileName="src/pages/index.astro"
<!-- astro -->
---
import { getIntlayer } from "intlayer";
import appContent from "../app.content";

const { title } = getIntlayer('app');
---

<html lang="en">
  <head>
    <meta charset="utf-8" />
    <meta name="viewport" content="width=device-width" />
    <title>{title}</title>
  </head>
  <body>
    <h1>{title}</h1>
  </body>
</html>
```

### Step 6: Localized routing

Create a dynamic route segment to serve localized pages, for example `src/pages/[locale]/index.astro`:

```astro fileName="src/pages/[locale]/index.astro"
<!-- astro -->
---
import { getIntlayer } from "intlayer";

const { title } = getIntlayer('app');
---

<h1>{title}</h1>
```

The Astro integration adds a Vite middleware during development that helps with locale-aware routing and environment definitions. You can still link between locales using your own logic, or utility functions like `getLocalizedUrl` from `intlayer`.

### Step 7: Continue using your favorite framework

Continue using your favorite framework to build your application.

- Intlayer + React: [Intlayer with React](https://github.com/aymericzip/intlayer/blob/main/docs/docs/en/intlayer_with_vite+react.md)
- Intlayer + Vue: [Intlayer with Vue](https://github.com/aymericzip/intlayer/blob/main/docs/docs/en/intlayer_with_vite+vue.md)
- Intlayer + Svelte: [Intlayer with Svelte](https://github.com/aymericzip/intlayer/blob/main/docs/docs/en/intlayer_with_vite+svelte.md)
- Intlayer + Solid: [Intlayer with Solid](https://github.com/aymericzip/intlayer/blob/main/docs/docs/en/intlayer_with_vite+solid.md)
- Intlayer + Preact: [Intlayer with Preact](https://github.com/aymericzip/intlayer/blob/main/docs/docs/en/intlayer_with_vite+preact.md)

### Configure TypeScript

Intlayer use module augmentation to get benefits of 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 allows you to avoid committing them to your Git repository.

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

```plaintext
# Ignore the files generated by Intlayer
.intlayer
```

### VS Code Extension

To improve 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/intlayer_visual_editor.md) or externalize your content using the [CMS](https://github.com/aymericzip/intlayer/blob/main/docs/docs/en/intlayer_CMS.md).

---
