Lingui's runtime API (@lingui/core setupI18n plus @lingui/react) replaces the core i18n shim in src/lib/i18n.ts, with the same surface as everywhere else: i18n.t(key, vars) and useT(). I'd pick it when you want ICU message syntax and a catalog CLI (bun run i18n:extract); pick i18next for the bigger plugin ecosystem, and none while you're still English-only. Screens don't change shape: they keep the shim's {{name}} placeholders, and toIcu() converts them to {name} at the t boundary.
When to pick Lingui
Lingui: Pick it for ICU messages and a catalog CLI (bun run i18n:extract).
At a glance
- Runs in Expo Go
- Yes
- Files added
- 11
- npm packages
- 4
- Keys to paste
- None
- Included in
- Starter and Pro
- Tests included
- 1
Set it up
bun run setup --i18n linguiSetup copies the module in, installs SDK-matched versions and removes the options you did not pick. Then bun run doctor lists every key still missing, with a link to where you get it. The step-by-step guide is in the Lingui docs.
Wiring it by hand instead? Read the guide: Expo i18n: i18next or Lingui, compared.
Lingui vs other i18n options
| Option | Expo Go | npm packages | Keys to paste | Included in |
|---|---|---|---|---|
| Lingui | Yes | 4 | 0 | Starter and Pro |
| i18next | Yes | 3 | 0 | Starter and Pro |
Questions
Can I use Lingui in Expo Go?
Yes. This module runs in Expo Go, so you can try it before you make a development build.
What do I need to set up Lingui in an Expo app?
Only bun run setup --i18n lingui. There are no API keys to paste; bun run doctor checks the result.
Which other modules does Lingui need?
It needs a Storage option (expo-sqlite/kv-store, MMKV or AsyncStorage). Pick those in the same setup run.
Does the ReadyNative free tier include Lingui?
No. It ships in Starter and Pro (one payment, lifetime updates); the free tier ships with i18n switched off.
Can I build the app without Lingui?
Yes. Pick none for i18n (bun run setup --i18n none) - i18n.t/useT return the English key.
Lingui or i18next for Expo?
Lingui: Pick it for ICU messages and a catalog CLI (bun run i18n:extract). i18next: The default. Pick it for the bigger ecosystem: plurals, formatters, translators who already know the format.
Which Lingui version does it install?
For Expo SDK 57: @lingui/core ^5.9.5, @lingui/message-utils ^5.9.5, @lingui/react ^5.9.5, expo-localization ~57.0.2. Setup installs Expo packages with expo install, so they match the SDK.
Get it
Lingui ships in Starter and Pro: one payment, lifetime updates. See pricing or browse every module.