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The Nudj APIs localise user-facing fields (challenge titles, reward descriptions, achievement copy, email templates, etc.) on the way out. Send the x-language header to control which language the API returns.

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The x-language header

x-language: en
  • Header name is case-insensitive. x-lang is accepted as a shortcut.
  • Value is a two-letter language code (en, fr, de, es, ja, zh, …) — the exact set supported by your organisation depends on the languages configured on your communities.
  • If the header is missing, the API falls back to the organisation’s default language.
  • If the value is an unsupported language, the API falls back to the organisation’s default language (no error).

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Which endpoints support it?

Both the Integration and Admin APIs respect x-language on every endpoint that returns translatable content — challenges, actions, rewards, achievements, emails, leaderboard configs, community rules, variable labels, and any custom copy written through the admin dashboard. The Analytics API returns raw metrics and is not affected by x-language.

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Sending the header

curl -X GET "https://{subdomain}.nudj.cx/api/v2/integration/challenges" \
  -H "Authorization: Bearer $NUDJ_API_TOKEN" \
  -H "x-language: fr"

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Response shape

Translatable fields come back pre-resolved — a single string in the requested language — rather than a map of { en: …, fr: … }. Your client doesn’t need to do any client-side locale matching: 
{
  "id": "…",
  "title": "Défi de la semaine",
  "description": "Complétez 3 actions pour gagner 100 XP"
}
If a specific field has no translation for the requested language, it falls back to the community’s default language for that field, then to the organisation’s default language.

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Best practices

  1. Send x-language from your user context. In a widget or integration that has a user’s locale preference, pass it through on every request — the API handles the fallback chain for you.
  2. Don’t pin every request to the organisation default. If you omit the header, you always get the org default. That’s fine for backend-only jobs (e.g. generating a CSV export), but for user-facing flows, send the user’s actual locale.
  3. Cache per-language. If you cache API responses on your side, make x-language part of the cache key — the same endpoint will return different payloads for different languages.

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Managing translations

Translations themselves are managed in the admin dashboard. See Questions & Variables for the template system used across emails and community copy.

Authentication

Full auth header matrix (includes every supported request header).

Pagination

The limit/skip contract on list endpoints.