Error envelope

Every error response from Production Board carries the same body: detail is the English fallback (kept for legacy / curl), i18n is the bilingual form clients prefer.

Response shape

{
  "detail": "Invalid credentials",
  "i18n":  { "en": "Invalid credentials", "de": "Ungültige Zugangsdaten" }
}

Status codes

Hover a code for a concrete example of what triggers it.