key-too-long¶


Title	Invalid Idempotency Key
HTTP status	`400 Bad Request`
`type`	`/errors/key-too-long`

What triggers it¶

The Idempotency-Key request header is longer than the maximum of 255 characters. This is checked before the request body is read and before any store call, so the handler never runs.

Example response¶

HTTP/1.1 400 Bad Request
Content-Type: application/problem+json

{
  "type": "https://eben-vranken.github.io/idempo-docs/errors/key-too-long/",
  "title": "Invalid Idempotency Key",
  "status": 400,
  "detail": "The Idempotency-Key header exceeds the maximum length of 255 characters",
  "instance": "/charge"
}

What the client should do¶

Use a shorter Idempotency-Key — 255 characters or fewer. A UUID (36 characters) or a random token of a few dozen characters is plenty. This is a client bug, not a transient condition: retrying the same oversized key will fail the same way.