idempotency_key_in_progress

HTTP 409 · A request with this key is still being processed.

What causes it

You retried before the first attempt finished. The original is still running, so a second one is refused rather than racing it.

What to do

Wait a second or two and retry with the same key.

Retry?

Yes — after a short delay, with the same key.

The response

{
  "type": "https://developers.vaki.co/errors/idempotency_key_in_progress",
  "title": "…",
  "status": 409,
  "code": "idempotency_key_in_progress",
  "detail": "…",
  "instance": "/v1/checkout_links"
}

Branch on code, never on title or detail. The full list of codes, and the shape of the problem document, is on Errors.