---
title: Project setup
description: Create the application configuration and mount the Vite integration.
order: 10
toc:
  - id: configuration
    title: Configuration
  - id: catalog-sources
    title: Catalog sources
  - id: vite-plugin
    title: Vite plugin
---

## Configuration {#configuration}

Create `i18n.config.json` in the consuming application:

```json
{
  "sourceLocale": "en-US",
  "locales": ["en-US", "zh-Hans"],
  "catalogPath": "src/locales/{locale}/messages",
  "catalogSources": ["@workspace/ui/locales/{locale}"],
  "include": ["src", "../../packages/ui/src"],
  "exclude": ["**/*.test.{ts,tsx}"]
}
```

This file is the application's single persistent internationalization configuration. CLI commands create temporary Lingui configuration only for the child process.

The workspace ships exactly two locales: American English (`en-US`) and Simplified Chinese (`zh-Hans`). Use those same locale keys for application catalogs and package catalog sources.

## Catalog sources {#catalog-sources}

Sources are merged from left to right, and the application catalog is always last. Put reusable package catalogs first so product-specific translations can override them.

## Vite plugin {#vite-plugin}

```ts
import { i18n } from "@workspace/i18n/vite"
import { defineConfig } from "vite"

export default defineConfig({
  plugins: [i18n()],
})
```

The plugin serves development catalog APIs and exposes the generated loader through `@workspace/i18n/catalogs`.