Creation:2026-06-05Last update:2026-06-05

    Migrating from react-i18next / i18next to Intlayer

    Why migrate from react-i18next / i18next to Intlayer?

    Instead of loading massive JSON files into your pages, load only the necessary content. Intlayer helps reduce your bundle and page sizes by up to 50%.

    Scoping your application's content facilitates maintenance for large-scale applications. You can duplicate or delete a single feature folder without the mental burden of reviewing your entire content codebase. Additionally, Intlayer is fully typed to ensure your content's accuracy.

    Intlayer is also the solution with the most active development in the i18n ecosystem — issues are fixed fast, new framework adapters land regularly, and the core API is continuously refined based on real-world production feedback.

    Co-locating content reduces the context needed by Large Language Models (LLMs). Intlayer also comes with a suite of tools, such as a CLI to test for missing translations, LSP, MCP, and agent skills, to make the developer experience (DX) even smoother for AI agents.

    Use automation to translate in your CI/CD pipeline using the LLM of your choice at the cost of your AI provider. Intlayer also offers a compiler to automate content extraction, as well as a web platform to help translate in the background.

    Connecting massive JSON files to components can lead to performance and reactivity issues. Intlayer optimizes your content loading at build time.

    More than just an i18n solution, Intlayer provides a self-hosted visual editor and a full CMS to help you manage your multilingual content in real-time, making collaboration with translators, copywriters, and other team members seamless. Content can be stored locally and/or remotely.

    Migration strategies

    There are two complementary strategies for migrating from react-i18next / i18next to Intlayer:

    1. Compat adapter (recommended for existing apps) — Install @intlayer/react-i18next (for React components) and/or @intlayer/i18next (for the core i18n instance). These packages expose the exact same API as react-i18next / i18next but delegate all translation work to Intlayer under the hood. You keep your existing useTranslation, Trans, withTranslation, i18next.t() calls — the only change is the import path.

    2. Full migration — Gradually replace react-i18next APIs with native Intlayer hooks (useIntlayer, IntlayerProvider) and co-locate content in .content.ts files alongside your components.

    This guide covers Strategy 1 first (drop-in compat adapter), then walks through the optional full migration.

    Table of Contents

    Quick migration

    The following steps are the minimum required to get your existing react-i18next app running on Intlayer with zero code changes.

    1. Install Dependencies

      Install the Intlayer core packages and the compat adapters:

      bash
      npm install intlayer react-intlayer @intlayer/react-i18next @intlayer/i18next @intlayer/sync-json-pluginnpx intlayer init
      You can keep react-i18next and i18next installed — the compat adapters use them as devDependencies / optional peerDependencies for TypeScript types. You don't need to change any package.json peers.

    2. Configure Intlayer

      The intlayer init command creates a starter intlayer.config.ts. Update it to match your existing locales and point the syncJSON plugin at your message files:

      intlayer.config.ts
      import { Locales, type IntlayerConfig } from "intlayer";
import { syncJSON } from "@intlayer/sync-json-plugin";

const config: IntlayerConfig = {
  internationalization: {
    locales: [
      Locales.ENGLISH,
      Locales.FRENCH,
      Locales.SPANISH,
      // Add all your existing locales here
    ],
    defaultLocale: Locales.ENGLISH,
  },
  plugins: [
    syncJSON({
      // matches react-i18next placeholder syntax: {{name}}
      format: "i18next",
      source: ({ locale }) => `./src/locales/${locale}.json`,
      location: "src/locales",
    }),
  ],
};

export default config;
      source maps a locale to its JSON file path. location tells the Intlayer watcher which folder to monitor for changes. The format: 'i18next' option ensures that placeholders like {{name}} are parsed correctly.

    3. Add the Intlayer Plugin to your Bundler

      Wrap your existing bundler config with the compat plugin. It composes the core Intlayer plugin, wires up content watching, and — critically — injects module aliases so that your existing import … from 'react-i18next' (and 'i18next') calls are transparently redirected to @intlayer/react-i18next / @intlayer/i18next at build time. No source file changes are needed.

      For Vite:

      vite.config.ts
      import { defineConfig } from "vite";
import react from "@vitejs/plugin-react";
import { reactI18nextVitePlugin } from "@intlayer/react-i18next/plugin";

export default defineConfig({
  plugins: [react(), reactI18nextVitePlugin()],
});
      reactI18nextVitePlugin() wraps vite-intlayer's intlayer() plugin and adds the react-i18next / i18next aliases. Using the plain intlayer() plugin from vite-intlayer compiles dictionaries but does not add those aliases — you would then rename imports to @intlayer/* manually (see Step 4).

      For Next.js:

      If you are using next-i18next (Pages Router integration), install @intlayer/next-i18next and next-intlayer:

      bash
      npm install @intlayer/next-i18next next-intlayer

      Then add the compat plugin to your next.config.ts (it injects the next-i18next / react-i18next / i18next aliases):

      next.config.ts
      import type { NextConfig } from "next";
import { createNextI18nPlugin } from "@intlayer/next-i18next/plugin";

const withIntlayer = createNextI18nPlugin();

const nextConfig: NextConfig = {
  /* your options */
};

export default withIntlayer(nextConfig);
      You no longer need i18next.init() or manual provider bootstrapping. Intlayer compiles all dictionaries at build time, so there is no runtime loading step. The aliased provider handles initialization for you.

    That's it for the quick migration. Your app now runs on Intlayer while keeping every react-i18next import and API intact.

    Typed translation keys — automatic. Once Intlayer compiles your dictionaries, useTranslation and getFixedT are typed against your actual content. Keys are autocompleted in your IDE and invalid paths cause TypeScript errors at build time — no extra setup required.

    tsx
    // 'about' is a registered dictionary key → t() only accepts valid dot-pathsconst { t } = useTranslation("about");t("counter.label"); // ✓ autocompletedt("does.not.exist"); // ✗ TypeScript error// Server-side (i18next instance)const tAbout = i18n.getFixedT(null, "about");tAbout("counter.label"); // ✓ typed

    Complete migration

    The steps below are optional and can be done incrementally. They unlock the full Intlayer feature set: visual editor, CMS, typed content files, AI-powered translation, and more.

    1. Explicit import renaming (optional)

      Tùy chọn

      The Intlayer plugins already handle aliasing at the bundler level. If you prefer to make the dependency explicit in your source files, you can rename imports manually:

      Before After
      import { useTranslation } from 'react-i18next' import { useTranslation } from '@intlayer/react-i18next'
      import { Trans } from 'react-i18next' import { Trans } from '@intlayer/react-i18next'
      import { withTranslation } from 'react-i18next' import { withTranslation } from '@intlayer/react-i18next'
      import { I18nextProvider } from 'react-i18next' import { I18nextProvider } from '@intlayer/react-i18next'
      import { initReactI18next } from 'react-i18next' import { initReactI18next } from '@intlayer/react-i18next'
      import i18next from 'i18next' import i18next from '@intlayer/i18next'
      import { createInstance } from 'i18next' import { createInstance } from '@intlayer/i18next'
      import { t } from 'i18next' import { t } from '@intlayer/i18next'

      For Next.js (next-i18next):

      Before After
      import { serverSideTranslations } from 'next-i18next/serverSideTranslations' import { serverSideTranslations } from '@intlayer/next-i18next'
      import { appWithTranslation } from 'next-i18next' import { appWithTranslation } from '@intlayer/next-i18next'
      import { useTranslation } from 'next-i18next' import { useTranslation } from '@intlayer/next-i18next'

    2. Enable AI-Powered Translation Automation

      Tùy chọn

      Once Intlayer is wired up, use its CLI to fill missing translations automatically:

      bash
      # Test for missing translations (add to CI)npx intlayer test# Fill missing translations with AInpx intlayer fill

      Add the AI configuration to intlayer.config.ts:

      intlayer.config.ts
      import { Locales, type IntlayerConfig } from "intlayer";
import { syncJSON } from "@intlayer/sync-json-plugin";

const config: IntlayerConfig = {
  internationalization: {
    locales: [Locales.ENGLISH, Locales.FRENCH, Locales.SPANISH],
    defaultLocale: Locales.ENGLISH,
  },
  plugins: [
    syncJSON({
      format: "i18next",
      source: ({ locale }) => `./src/locales/${locale}.json`,
      location: "src/locales",
    }),
  ],
  ai: {
    apiKey: process.env.OPENAI_API_KEY,
    // provider: "openai",     // default
    // model: "gpt-4o-mini",   // default
  },
};

export default config;
      See Intlayer CLI documentation for all available options.

    What you can delete after migration

    Once the compat adapters are in place, the following react-i18next / i18next boilerplate can be removed:

    File / pattern Why it's no longer needed
    i18next.init() calls Intlayer's provider initializes everything automatically; there is no runtime loading step.
    I18nextProvider / initReactI18next The Intlayer plugin handles injection and bootstrapping under the hood.
    JSON language bundles (locales/*.json) JSON bundles are only needed if you still use the syncJSON plugin. Once you migrate to .content.ts files you can delete the JSON folder.

    When you are ready to go further, Intlayer automatically discovers all .content.ts and .content.json files anywhere in your codebase (by default, anywhere inside ./src). You can place a my-component.content.ts file right next to your MyComponent.tsx and Intlayer will pick it up at build time with no additional configuration — no imports, no registration, no centralized index file needed. This makes co-locating translations with pages and components completely frictionless.

    Configure TypeScript

    Intlayer uses module augmentation to provide full TypeScript intellisense for your translation keys. Make sure your tsconfig.json includes the auto-generated types:

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

    Git Configuration

    Add Intlayer's generated directory to your .gitignore:

    .gitignore
    # Ignore the files generated by Intlayer.intlayer

    Go Further

    Tại sao Intlayer?