\n\n
\n\n\n\n{@const Title = $content.title}
\n\n\n\n\n```\n\n> If your app already exists, you can use the [Intlayer Compiler](/doc/compiler), as well as the [extract command](/doc/concept/cli/extract), to transform thousands of components in a second.\n\n### (Optional) Step 6: Change the language of your content\n\n```svelte fileName=\"src/App.svelte\"\n\n\n\n \n```\n\n#### Configure Server-Side Routing (Optional)\n\nIn parallel, you can also use the `intlayerProxy` to add server-side routing to your application. This plugin will automatically detect the current locale based on the URL and set the appropriate locale cookie. If no locale is specified, the plugin will determine the most appropriate locale based on the user's browser language preferences. If no locale is detected, it will redirect to the default locale.\n\n> Note that to use the `intlayerProxy` in production, you need to switch the `vite-intlayer` package from `devDependencies` to `dependencies`.\n\n```typescript {3,7} fileName=\"vite.config.ts\" codeFormat={[\"typescript\", \"esm\", \"commonjs\"]}\nimport { defineConfig } from \"vite\";\nimport { svelte } from \"@sveltejs/vite-plugin-svelte\";\nimport { intlayer, intlayerProxy } from \"vite-intlayer\";\n\n// https://vitejs.dev/config/\nexport default defineConfig({\n plugins: [\n intlayerProxy(), // should be placed first\n svelte(),\n intlayer(),\n ],\n});\n```\n\n### (Optional) Step 8: Change the URL when the locale changes\n\nTo allow users to switch languages and update the URL accordingly, you can create a `LocaleSwitcher` component. This component will use `getLocalizedUrl` from `intlayer` and `push` from `svelte-spa-router`.\n\n```svelte fileName=\"src/lib/LocaleSwitcher.svelte\"\n\n\n\n \n\nRun the extractor to transform your components and extract the content\n\n```bash packageManager=\"npm\"\nnpx intlayer extract\n```\n\n```bash packageManager=\"pnpm\"\npnpm intlayer extract\n```\n\n```bash packageManager=\"yarn\"\nyarn intlayer extract\n```\n\n```bash packageManager=\"bun\"\nbun x intlayer extract\n```\n\n \n \n\nUpdate your `vite.config.ts` to include the `intlayerCompiler` plugin:\n\n```ts fileName=\"vite.config.ts\"\nimport { defineConfig } from \"vite\";\nimport { intlayer, intlayerCompiler } from \"vite-intlayer\";\n\nexport default defineConfig({\n plugins: [\n intlayer(),\n intlayerCompiler(), // Adds the compiler plugin\n ],\n});\n```\n\n```bash packageManager=\"npm\"\nnpm run build # Or npm run dev\n```\n\n```bash packageManager=\"pnpm\"\npnpm run build # Or pnpm run dev\n```\n\n```bash packageManager=\"yarn\"\nyarn build # Or yarn dev\n```\n\n```bash packageManager=\"bun\"\nbun run build # Or bun run dev\n```\n\n \n \n\n### (Optional) Sitemap and robots.txt (build-time)\n\nIntlayer includes formatters such as `generateSitemap` and `getMultilingualUrls` that produce crawler-ready multilingual `sitemap.xml` and `robots.txt` output you can write into your project’s `public/` folder. In practice you run a small Node script **before** Vite (for example `predev` / `prebuild` npm hooks) so those files exist when you build or serve the app.\n\n#### Sitemap\n\nIntlayer’s sitemap generator respects your locale setup and includes the usual metadata for crawlers.\n\n> The generated sitemap supports the `xhtml:link` namespace (hreflang XML extensions). Unlike basic generators that only emit flat URLs, Intlayer wires bidirectional links between every localized variant of each page (for example `/about`, `/fr/about`, or `/about?lang=fr`, depending on your routing mode), which helps search engines relate localized URLs.\n\n#### Robots.txt\n\nUse `getMultilingualUrls` so `Disallow` entries cover every localized spelling of sensitive paths.\n\n#### 1. Add `generate-seo.mjs` at the project root\n\n```javascript fileName=\"generate-seo.mjs\"\nimport fs from \"fs\";\nimport path from \"path\";\nimport { fileURLToPath } from \"url\";\nimport { generateSitemap, getMultilingualUrls } from \"intlayer\";\n\nconst __dirname = path.dirname(fileURLToPath(import.meta.url));\n\nconst SITE_URL = (process.env.SITE_URL || \"http://localhost:5173\").replace(\n /\\/$/,\n \"\"\n);\n\nconst pathList = [\n { path: \"/\", changefreq: \"daily\", priority: 1.0 },\n { path: \"/about\", changefreq: \"monthly\", priority: 0.7 },\n];\n\nconst sitemapXml = generateSitemap(pathList, { siteUrl: SITE_URL });\nfs.writeFileSync(path.join(__dirname, \"public\", \"sitemap.xml\"), sitemapXml);\n\nconst getAllMultilingualUrls = (urls) =>\n urls.flatMap((url) => Object.values(getMultilingualUrls(url)));\n\nconst disallowedPaths = getAllMultilingualUrls([\"/admin\", \"/private\"]);\n\nconst robotsTxt = [\n \"User-agent: *\",\n \"Allow: /\",\n ...disallowedPaths.map((path) => `Disallow: ${path}`),\n \"\",\n `Sitemap: ${SITE_URL}/sitemap.xml`,\n].join(\"\\n\");\n\nfs.writeFileSync(path.join(__dirname, \"public\", \"robots.txt\"), robotsTxt);\n\nconsole.log(\"SEO files generated successfully.\");\n```\n\n`intlayer` must be installed so the script can import it. Set `SITE_URL` in the environment for production (for example in CI).\n\n> Prefer `generate-seo.mjs` for Node ESM. If you use `generate-seo.js` instead, ensure `\"type\": \"module\"` is set in `package.json`, or run Node with ESM enabled.\n\n#### 2. Run the script before Vite\n\n```json fileName=\"package.json\"\n{\n \"scripts\": {\n \"dev\": \"vite\",\n \"prebuild\": \"node generate-seo.mjs\",\n \"build\": \"vite build\",\n \"preview\": \"vite preview\"\n }\n}\n```\n\nAdjust if you use pnpm or yarn. You can also invoke the same script from CI or another step if that fits your workflow.\n\n### Git Configuration\n\nIt is recommended to ignore the files generated by Intlayer. This allows you to avoid committing them to your Git repository.\n\nTo do this, you can add the following instructions to your `.gitignore` file:\n\n```bash\n# Ignore the files generated by Intlayer\n.intlayer\n```\n\n### VS Code Extension\n\nTo improve your development experience with Intlayer, you can install the official **Intlayer VS Code Extension**.\n\n[Install from the VS Code Marketplace](https://marketplace.visualstudio.com/items?itemName=intlayer.intlayer-vs-code-extension)\n\nThis extension provides:\n\n- **Autocompletion** for translation keys.\n- **Real-time error detection** for missing translations.\n- **Inline previews** of translated content.\n- **Quick actions** to easily create and update translations.\n\nFor more details on how to use the extension, refer to the [Intlayer VS Code Extension documentation](https://intlayer.org/doc/vs-code-extension).\n\n---\n\n### Go Further\n\nTo go further, you can implement the [visual editor](/doc/concept/editor) or externalize your content using the [CMS](/doc/concept/cms).\n","about":"Discover how to make your Vite and Svelte website multilingual. Follow the documentation to internationalize (i18n) and translate it.","url":"https://intlayer.org/doc/environment/vite-and-svelte","datePublished":"18-04-2025","dateModified":"06-05-2026","keywords":"Internationalization, Documentation, Intlayer, Vite, Svelte, JavaScript","license":"https://raw.githubusercontent.com/aymericzip/intlayer/refs/heads/main/LICENSE","audience":{"@type":"Audience","audienceType":"Developers, Content Managers"}}
1. Add
{$content.title}
\n\n{@const Title = $content.title}
\n\n\n\n\n```\n\n> If your app already exists, you can use the [Intlayer Compiler](/doc/compiler), as well as the [extract command](/doc/concept/cli/extract), to transform thousands of components in a second.\n\n### (Optional) Step 6: Change the language of your content\n\n```svelte fileName=\"src/App.svelte\"\n\n\n\n \n
\n```\n\n### (Optional) Step 7: Render Markdown and HTML\n\nIntlayer supports rendering Markdown and HTML content in Svelte.\n\nBy default, Intlayer treats Markdown and HTML as interactive components or strings. To render them in Svelte, you can use the `{@const Component = ...}\n
\n\n \n\n \n
\n```\n\n### (Optional) Step 9: Internationalized Links\n\nFor SEO, it is recommended to prefix your routes with the locale (e.g., `/about`, `/fr/about`).\n\n```svelte fileName=\"src/lib/components/Link.svelte\"\n\n\n\n Creation:2025-04-18Last update:2026-05-06
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Version History
- "Update Solid useIntlayer API usage to direct property access"v8.9.05/4/2026
- "Add init command"v7.5.912/30/2025
- "Update documentation"v5.5.1111/19/2025
- "Initial history"v5.5.106/29/2025
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Translate your Vite and Svelte website using Intlayer | Internationalization (i18n)
Table of Contents
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 a Vite and Svelte Application
See Application Template on GitHub.
Step 1: Install Dependencies
Install the necessary packages using npm:
bash
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npm install intlayer svelte-intlayernpm install vite-intlayer --save-devnpx intlayer initintlayer
The core package that provides internationalization tools for configuration management, translation, content declaration, transpilation, and CLI commands.
svelte-intlayer The package that integrates Intlayer with Svelte application. It provides context providers and hooks for Svelte internationalization.
vite-intlayer Includes the Vite plugin for integrating Intlayer with the Vite bundler, 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:
intlayer.config.ts
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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.
Step 3: Integrate Intlayer in Your Vite Configuration
Add the intlayer plugin into your configuration.
vite.config.ts
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import { defineConfig } from "vite";import { svelte } from "@sveltejs/vite-plugin-svelte";import { intlayer } from "vite-intlayer";// https://vitejs.dev/config/export default defineConfig({ plugins: [svelte(), intlayer()],});The intlayer() Vite plugin is used to integrate Intlayer with Vite. It ensures the building of content declaration files and monitors them in development mode. It defines Intlayer environment variables within the Vite application. Additionally, it provides aliases to optimize performance.
Step 4: Declare Your Content
Create and manage your content declarations to store translations:
src/app.content.tsx
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import { t, type Dictionary } from "intlayer";
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 thecontentDirdirectory (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.
Step 5: Utilize Intlayer in Your Code
src/App.svelte
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<script> import { useIntlayer } from "svelte-intlayer"; const content = useIntlayer("app");</script><div><!-- Render content as simple content --><h1>{$content.title}</h1><!-- To render the content editable using the editor --><h1>{@const Title = $content.title}<Title /></h1><!-- To render the content as a string --><div aria-label={$content.title.value}></div><div aria-label={$content.title.toString()}></div><div aria-label={String($content.title)}></div>If your app already exists, you can use the Intlayer Compiler, as well as the extract command, to transform thousands of components in a second.
(Optional) Step 6: Change the language of your content
src/App.svelte
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<script lang="ts">import { getLocaleName } from 'intlayer';import { useLocale } from "svelte-intlayer";// Get locale information and setLocale functionconst { locale, availableLocales, setLocale } = useLocale();// Handle locale changeconst changeLocale = (event: Event) => { const target = event.target as HTMLSelectElement; const newLocale = target.value; setLocale(newLocale);};</script><div> <select value={$locale} on:change={changeLocale}> {#each availableLocales ?? [] as loc} <option value={loc}> {getLocaleName(loc)} </option> {/each} </select></div>(Optional) Step 7: Render Markdown and HTML
Intlayer supports rendering Markdown and HTML content in Svelte.
By default, Intlayer treats Markdown and HTML as interactive components or strings. To render them in Svelte, you can use the {@const Component = ...}<Component /> for components or {@html ...} for plain strings.
src/App.svelte
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<script> import { useIntlayer } from "svelte-intlayer"; const content = useIntlayer("app");</script><!-- Render Markdown as a Component -->{@const MyMarkdownContent = $content.myMarkdownContent}<MyMarkdownContent /><!-- Render HTML Content -->{@html $content.myHtmlContent.toString()}<!-- Render with custom component overrides -->{@const MyMarkdownContent = $content.myMarkdownContent.use({ h1: (props) => { const h1 = document.createElement('h1'); h1.style.color = 'red'; h1.textContent = props.children; return h1; }, MyCustomComponent: () => { const div = document.createElement('div'); div.textContent = 'Custom Logic'; return div; } })}<MyMarkdownContent />TIP You can also access your markdown front-matter data using the$content.markdownContent.metadata.xxxproperty.
(Optional) Step 8: Set up the intlayer editor / CMS
To set up the intlayer editor, you must follow the intlayer editor documentation.
To set up the intlayer CMS, you must follow the intlayer CMS documentation.
(Optional) Step 7: Add localized Routing to your application
To handle localized routing in your Svelte application, you can use svelte-spa-router along with Intlayer's localeFlatMap to generate routes for each locale.
First, install svelte-spa-router:
bash
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npm install svelte-spa-routernpx intlayer initThen, create a Router.svelte file to define your routes:
src/Router.svelte
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<script lang="ts">import { localeFlatMap } from "intlayer";import Router from "svelte-spa-router";import { wrap } from "svelte-spa-router/wrap";import App from "./App.svelte";const routes = Object.fromEntries( localeFlatMap(({locale, urlPrefix}) => [ [ urlPrefix || '/', wrap({ component: App as any, props: { locale, }, }), ], ]));</script><Router {routes} />Update your main.ts to mount the Router component instead of App:
src/main.ts
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import { mount } from "svelte";import Router from "./Router.svelte";const app = mount(Router, { target: document.getElementById("app")!,});export default app;Finally, update your App.svelte to receive the locale prop and use it with useIntlayer:
src/App.svelte
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<script lang="ts">import type { Locale } from 'intlayer';import { useIntlayer } from "svelte-intlayer";import Counter from './lib/Counter.svelte';import LocaleSwitcher from './lib/LocaleSwitcher.svelte';export let locale: Locale;$: content = useIntlayer('app', locale);</script><main> <div class="locale-switcher-container"> <LocaleSwitcher currentLocale={locale} /> </div> <!-- ... rest of your app ... --></main>Configure Server-Side Routing (Optional)
In parallel, you can also use the intlayerProxy to add server-side routing to your application. This plugin will automatically detect the current locale based on the URL and set the appropriate locale cookie. If no locale is specified, the plugin will determine the most appropriate locale based on the user's browser language preferences. If no locale is detected, it will redirect to the default locale.
Note that to use theintlayerProxyin production, you need to switch thevite-intlayerpackage fromdevDependenciestodependencies.
vite.config.ts
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import { defineConfig } from "vite";
import { svelte } from "@sveltejs/vite-plugin-svelte";
import { intlayer, intlayerProxy } from "vite-intlayer";
// https://vitejs.dev/config/
export default defineConfig({
plugins: [
intlayerProxy(), // should be placed first
svelte(),
intlayer(),
],
});(Optional) Step 8: Change the URL when the locale changes
To allow users to switch languages and update the URL accordingly, you can create a LocaleSwitcher component. This component will use getLocalizedUrl from intlayer and push from svelte-spa-router.
src/lib/LocaleSwitcher.svelte
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<script lang="ts">import { getLocaleName, getLocalizedUrl } from "intlayer";import { useLocale } from "svelte-intlayer";import { push } from "svelte-spa-router";export let currentLocale: string | undefined = undefined;// Get locale informationconst { locale, availableLocales } = useLocale();// Handle locale changeconst changeLocale = (event: Event) => { const target = event.target as HTMLSelectElement; const newLocale = target.value; const currentUrl = window.location.pathname; const url = getLocalizedUrl( currentUrl, newLocale); push(url);};</script><div class="locale-switcher"> <select value={currentLocale ?? $locale} onchange={changeLocale}> {#each availableLocales ?? [] as loc} <option value={loc}> {getLocaleName(loc)} </option> {/each} </select></div>(Optional) Step 9: Internationalized Links
For SEO, it is recommended to prefix your routes with the locale (e.g., /about, /fr/about).
src/lib/components/Link.svelte
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<script lang="ts"> import { getLocalizedUrl } from "intlayer"; import { useLocale } from "svelte-intlayer"; export let href = ""; const { locale } = useLocale(); // Helper to prefix URL $: localizedHref = getLocalizedUrl(href, $locale);</script><a href={localizedHref}> <slot /></a>(Optional) Step 10: Extract the content of your components
If you have an existing codebase, transforming thousands of files can be time-consuming.
To ease this process, Intlayer propose a compiler / extractor to transform your components and extract the content.
To set it up, you can add a compiler section in your intlayer.config.ts file:
intlayer.config.ts
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import { type IntlayerConfig } from "intlayer";
const config: IntlayerConfig = {
// ... Rest of your config
compiler: {
/**
* Indicates if the compiler should be enabled.
*/
enabled: true,
/**
* Defines the output files path
*/
output: ({ fileName, extension }) => `./${fileName}${extension}`,
/**
* Indicates if the components should be saved after being transformed.
*
* - If `true`, the compiler will rewrite the component file in the disk. So the transformation will be permanent, and the compiler will skip the transformation for the next process. That way, the compiler can transform the app, and then it can be removed.
*
* - If `false`, the compiler will inject the `useIntlayer()` function call into the code in the build output only, and keep the base codebase intact. The transformation will be done only in memory.
*/
saveComponents: false,
/**
* Dictionary key prefix
*/
dictionaryKeyPrefix: "",
},
};
export default config;Run the extractor to transform your components and extract the content
bash
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npx intlayer extract(Optional) Sitemap and robots.txt (build-time)
Intlayer includes formatters such as generateSitemap and getMultilingualUrls that produce crawler-ready multilingual sitemap.xml and robots.txt output you can write into your project’s public/ folder. In practice you run a small Node script before Vite (for example predev / prebuild npm hooks) so those files exist when you build or serve the app.
Sitemap
Intlayer’s sitemap generator respects your locale setup and includes the usual metadata for crawlers.
The generated sitemap supports thexhtml:linknamespace (hreflang XML extensions). Unlike basic generators that only emit flat URLs, Intlayer wires bidirectional links between every localized variant of each page (for example/about,/fr/about, or/about?lang=fr, depending on your routing mode), which helps search engines relate localized URLs.
Robots.txt
Use getMultilingualUrls so Disallow entries cover every localized spelling of sensitive paths.
1. Add generate-seo.mjs at the project root
generate-seo.mjs
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import fs from "fs";import path from "path";import { fileURLToPath } from "url";import { generateSitemap, getMultilingualUrls } from "intlayer";const __dirname = path.dirname(fileURLToPath(import.meta.url));const SITE_URL = (process.env.SITE_URL || "http://localhost:5173").replace( /\/$/, "");const pathList = [ { path: "/", changefreq: "daily", priority: 1.0 }, { path: "/about", changefreq: "monthly", priority: 0.7 },];const sitemapXml = generateSitemap(pathList, { siteUrl: SITE_URL });fs.writeFileSync(path.join(__dirname, "public", "sitemap.xml"), sitemapXml);const getAllMultilingualUrls = (urls) => urls.flatMap((url) => Object.values(getMultilingualUrls(url)));const disallowedPaths = getAllMultilingualUrls(["/admin", "/private"]);const robotsTxt = [ "User-agent: *", "Allow: /", ...disallowedPaths.map((path) => `Disallow: ${path}`), "", `Sitemap: ${SITE_URL}/sitemap.xml`,].join("\n");fs.writeFileSync(path.join(__dirname, "public", "robots.txt"), robotsTxt);console.log("SEO files generated successfully.");intlayer must be installed so the script can import it. Set SITE_URL in the environment for production (for example in CI).
Prefergenerate-seo.mjsfor Node ESM. If you usegenerate-seo.jsinstead, ensure"type": "module"is set inpackage.json, or run Node with ESM enabled.
2. Run the script before Vite
package.json
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{ "scripts": { "dev": "vite", "prebuild": "node generate-seo.mjs", "build": "vite build", "preview": "vite preview" }}Adjust if you use pnpm or yarn. You can also invoke the same script from CI or another step if that fits your workflow.
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:
bash
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# Ignore the files generated by Intlayer.intlayerVS Code Extension
To improve your development experience with Intlayer, you can install the official Intlayer VS Code Extension.
Install from the VS Code Marketplace
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.
Go Further
To go further, you can implement the visual editor or externalize your content using the CMS.