i18n Config | DirectoryLaunch

Enable next-intl multi-language routing in DirectoryLaunch, configure locales, add messages files, and ship a header language switcher to your visitors.

File: config/i18n.config.ts

Off by default. When enabled, the site routes users to /<locale>/... URLs and loads translations from messages/{locale}.json.

Two switches

Enable both i18n: true in features.config.ts and enabled: true in i18n.config.ts. The feature flag gates the middleware; the config flag gates the routing logic.

Setup

1. Enable the flag

config/features.config.ts

export const featuresConfig = {
  // ...
  i18n: true,
};

2. Configure locales

config/i18n.config.ts

export const i18nConfig = {
  enabled: true,                   // master switch
  defaultLocale: 'en' as const,
  locales: ['en', 'ru', 'es'] as const,
  localeCookie: 'NEXT_LOCALE',
  localeDetection: true,           // auto-detect from Accept-Language
};

Field	What it does
`enabled`	Master switch. `false` = zero routing impact.
`defaultLocale`	Fallback when a translation is missing.
`locales`	All supported languages. Each needs a `messages/{code}.json`.
`localeCookie`	Cookie name for saving the user's choice.
`localeDetection`	Auto-detect language from browser headers on first visit.

3. Add translation files

Generate a locale file with AI, or copy en.json by hand and translate the strings.

Each locale needs its own file alongside the baseline:

messages/
├── en.json     ← required, the baseline
├── ru.json
└── es.json

Each file has the same structure as en.json.

4. The language switcher

Already in the header when i18n is on. Users can change language at any time.

How URLs work

en is the default — URL stays clean: /, /pricing, /submit
Other locales get a prefix — /ru/, /ru/pricing, /ru/submit
All links inside the app use next-intl's Link helper — it auto-prefixes.

What gets translated

Every string in messages/{locale}.json
Email templates (when using translation keys)
Validation error messages (when using keys)

What doesn't get auto-translated:

User-generated content (project names, descriptions, comments)
The blog (content/blog/*.mdx — write per-locale articles manually)
Legal pages (Terms, Privacy) — translate manually in messages/

Keep i18n off if you don't need it

enabled: false means zero routing or rendering overhead. Leave it off until you really have translated content — enabling it adds complexity to everything from links to SEO.