Installation

SayKit is split into a small core runtime and a set of optional packages for configuration, formatters, transformers, and framework integrations. Pick the pieces you need.

What to install

Every SayKit project needs the same set of pieces:

Package	Why
`saykit`	The core runtime, the `Say` class and ICU formatting
`@saykit/config`	The config schema (`defineConfig`) and the `saykit` CLI
One formatter	Reads and writes your translation files (e.g. `@saykit/format-po`)
One or more transformers	Extracts and rewrites macros from your source files
One build-tool plugin	Wires the transformer into your bundler

The build-tool plugin and the transformers do different jobs: the transformer knows how to parse and rewrite .ts/.tsx source, the plugin knows how to hook your bundler. You usually install both.

Quick install

For a React + Vite project, including TanStack Start (or any other unplugin-compatible bundler):

pnpm add saykit @saykit/react pnpm add -D @saykit/config @saykit/format-po
@saykit/transform-js @saykit/transform-jsx unplugin-saykit

npm install saykit @saykit/react npm install -D @saykit/config @saykit/format-po
@saykit/transform-js @saykit/transform-jsx unplugin-saykit

yarn add saykit @saykit/react yarn add -D @saykit/config @saykit/format-po
@saykit/transform-js @saykit/transform-jsx unplugin-saykit

bun add saykit @saykit/react bun add -D @saykit/config @saykit/format-po
@saykit/transform-js @saykit/transform-jsx unplugin-saykit

For a Next.js, React Native, Expo, or other Babel-driven project:

pnpm add saykit @saykit/react pnpm add -D @saykit/config @saykit/format-po
@saykit/transform-js @saykit/transform-jsx babel-plugin-saykit

npm install saykit @saykit/react npm install -D @saykit/config @saykit/format-po
@saykit/transform-js @saykit/transform-jsx babel-plugin-saykit

yarn add saykit @saykit/react yarn add -D @saykit/config @saykit/format-po
@saykit/transform-js @saykit/transform-jsx babel-plugin-saykit

bun add saykit @saykit/react bun add -D @saykit/config @saykit/format-po
@saykit/transform-js @saykit/transform-jsx babel-plugin-saykit

For a Carbon Discord bot (with tsdown + Cloudflare Workers):

pnpm add saykit @saykit/carbon pnpm add -D @saykit/config @saykit/format-po
@saykit/transform-js unplugin-saykit

npm install saykit @saykit/carbon npm install -D @saykit/config @saykit/format-po
@saykit/transform-js unplugin-saykit

yarn add saykit @saykit/carbon yarn add -D @saykit/config @saykit/format-po
@saykit/transform-js unplugin-saykit

bun add saykit @saykit/carbon bun add -D @saykit/config @saykit/format-po
@saykit/transform-js unplugin-saykit

Package directory

saykit

The core runtime. Exports the Say class. Almost every SayKit app depends on it.

@saykit/config

The config schema, the saykit CLI, and shared building blocks used by plugins and custom transformers.

@saykit/react

React integration. <Say>, SayProvider, useSay, server runtime helpers.

@saykit/carbon

Carbon Discord-bot integration. SayPlugin, withSay, locale-aware interaction.say.

unplugin-saykit

Universal bundler plugin: Vite, Rollup, Rolldown, Webpack, Rspack, esbuild, Farm, Bun.

babel-plugin-saykit

Babel plugin. Use this for Next.js, React Native, Metro, Expo, or any Babel-driven pipeline.

@saykit/format-po

Gettext PO formatter, the default for SayKit examples.

@saykit/transform-js / -jsx

The macro transformers for .js/.ts and .jsx/.tsx. Used by the build-tool plugins.

Peer dependencies

A few packages have peer requirements worth knowing about:

@saykit/react peers react and saykit. The package uses the react-server export condition for server rendering, so React 18+ is required and React 19+ is recommended.
@saykit/carbon peers @buape/carbon and saykit.
babel-plugin-saykit expects @babel/core (you almost certainly already have it).

Next: quickstart

If this is your first SayKit project, the quickstart walks through the whole loop (config, source, extraction, and runtime) in a few minutes.