cli

name	cli
description	Extract source strings, generate locale files, and remove unused keys for Better Translate projects.

CLI Skill

Use this guide when you want the CLI to manage locale files for you, or when you want to write source strings directly in code without naming keys by hand.

What this package does

• bt extract — scans your source files for t("...", { bt: true }) calls, adds keys to your source locale JSON, and rewrites those calls to plain key strings
• bt generate — reads your source locale file and calls an AI model to create translated versions for every other locale
• bt purge — scans your codebase for translation keys that are no longer referenced in any t("...") call and removes them from all locale files

Minimum setup

1. Install

npm install -D @better-translate/cli ollama-ai-provider-v2

2. Create a source locale file

Create src/messages/en.json:

{}

An empty object is fine. bt extract will populate it.

3. Create the config

Create better-translate.config.ts:

import { createOllama } from "ollama-ai-provider-v2";
import { defineConfig } from "@better-translate/cli/config";

const ollama = createOllama({
  baseURL: process.env.OLLAMA_BASE_URL ?? "http://localhost:11434/api",
});

export default defineConfig({
  sourceLocale: "en",
  locales: ["es", "fr"],
  model: ollama("qwen3:4b"),
  messages: {
    entry: "./src/messages/en.json",
  },
});

If you use Ollama, install ollama-ai-provider-v2. If you use a hosted provider, install the matching AI SDK provider package.

The CLI stays provider-agnostic. Swap ollama(...) for any other AI SDK provider model if you use a different provider.

4. Mark strings in your code

In any TypeScript or TSX file, write source text directly using { bt: true }:

t("Hello world", { bt: true });
t("Hello {name}", { bt: true, params: { name: "" } });

5. Extract

npx bt extract

The CLI automatically finds better-translate.config.ts in the project root. --config is only needed if the config file is in a non-standard location.

After this runs, the source locale file gains new keys and the original t() calls are rewritten:

// before
t("Hello world", { bt: true });

// after
t("components.header.helloWorld");

The namespace prefix (components.header) comes from the source file path. bt: true is removed. Other options like params are preserved.

6. Generate

npx bt generate

This creates one translated JSON file per locale next to the source file.

If markdown.rootDir is configured and the run would create or overwrite translated .md or .mdx files, the CLI asks for confirmation. Pass --yes or -y to skip:

npx bt generate --yes

7. Purge unused keys

npx bt purge

This finds translation keys that no longer appear in any t("...") call and removes them from all locale files. It asks you to confirm each key before removing it:

? Purge unused key "home.oldTitle"? (y/N) y
? Purge unused key "sidebar.legacy"? (y/N) n

Type y to remove a key, n (or just Enter) to keep it.

To remove all unused keys at once without prompting:

npx bt purge --yes

To preview what would be removed without making changes:

npx bt purge --dry-run

Dynamic keys: If code uses a dynamic key like t(`section.${id}`), the CLI cannot statically resolve it. It will warn you, protect keys sharing the detected prefix, or mark the key unsafe and skip it rather than silently deleting something that may still be in use.

Command reference

Command	Flag	Description
bt extract		Scan for bt: true calls, sync source locale, rewrite calls
	--config <path>	Path to config file (default: auto-detected)
	--dry-run	Preview changes without writing
	--max-length <n>	Max segment length for generated key names
bt generate		Translate source locale into all target locale files
	--config <path>	Path to config file
	--dry-run	Preview changes without writing
	--yes, -y	Skip confirmation for markdown file writes
bt purge		Remove unused translation keys from all locale files
	--config <path>	Path to config file
	--dry-run	Preview which keys would be removed without writing
	--yes, -y	Remove all unused keys without prompting

Rule

Always run bt extract before bt generate. Extract populates the source file; generate reads it.

After removing old features or refactoring key usage, run bt purge to clean up orphaned keys across all locale files.

Keep TypeScript autocomplete available

The CLI only manages files. Autocomplete at runtime still comes from the shared exported translator you create in @better-translate/core.

• Keep one exported translator
• Point your runtime packages and helpers back to that translator
• Let extracted keys flow into the same typed messages source

When to also add framework adapters

The CLI only manages files. You still need a runtime package to use them.

• Add @better-translate/core to load and use locale files at runtime
• Add @better-translate/react for React components
• Add @better-translate/nextjs for Next.js routing

Examples

• examples/nextjs-example — Next.js App Router with generated locale files
• examples/react-vite-example — React SPA with generated locale files
• examples/core-elysia-example — plain TypeScript/Node.js setup