i18n Config | DirectoryLaunch

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

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

Each file has the same structure — copy en.json and translate the strings.

AI Prompt· Generate a translation file

Generate messages/{locale-code, e.g. "ru" or "es"}.json by translating every key and value in messages/en.json to {target language, e.g. "Russian" or "Spanish"}.

Rules:

Preserve the exact JSON structure, keys, and nesting.
Translate only the string values — never the keys.
Keep \{placeholders\} in curly braces intact (those are next-intl variables).
For brand-specific terms like "DirectoryKit", decide: translate if it reads naturally localized, otherwise keep English.
Match the tone of the English source (friendly/professional, not overly formal).

Don't touch messages/en.json.

4. The language switcher

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

Language switcher in the site header

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.