File type not allowed for this key

HTTP 403 · format-not-allowed — ← all Webpath errors

The key's formats allowlist excludes this file type.

How to recover. Write an allowed extension, or use a key without the formats limit.

Example response

{
  "type": "https://muse.as/a/webpath/errors/format-not-allowed",
  "title": "File type not allowed for this key",
  "status": 403,
  "detail": "Write an allowed extension, or use a key without the formats limit."
}

This page documents the format-not-allowed error type returned in Webpath RFC 7807 application/problem+json responses. The machine-readable detail field carries a recovery hint you can show a user verbatim — see the Spec §12 and API Reference.