invalid_developer_key

What it means

Missing, invalid, revoked or expired ACE developer key. There is no partial-credit anonymous fallback — a header that does not resolve to a known key fails the same way as no header at all.

How to recognise it

The gateway answers HTTP 401 with x-ace-error: invalid_developer_key on the response, and a body in the shared error envelope:

{
  "error": {
    "message": "...",
    "type": "invalid_developer_key",
    "code": 401
  }
}

On a vendor-shaped surface (/anthropic/…, /gemini/…, /bedrock/…) the body wears that vendor's error envelope instead; the x-ace-error header is the same everywhere.

Is it ACE or the provider?

x-ace-error is present only on errors ACE originated. A vendor error relayed from upstream — a real provider 429, a provider 401 for a bad pass-through key — carries no x-ace-error, and its own type and code mean what the provider says. Read the header before deciding whether to retry, re-mint a key or surface the error.

Other 401 errors

• idp_authentication_error: A deployment fronted by a corporate identity provider refused the caller's IdP token.

Related

• Error contracts & status codes: the full taxonomy
• Response header specification
• Echo mode: reproduce a call without spending