idempotent key length is ### characters long, which is outside accepted lengths. idempotent keys must be #-### characters long. if you're looking for a decent generator, try using a uuid defined by ietf rfc ####.

Stripe API · POST /v1/customers · HTTP 400 idempotency_error

Status: ✅ verified:server:sandbox · first seen 2026-10-24 · last confirmed 2026-10-26 · 11 confirmations from 2 vantages

An Idempotency-Key longer than 255 characters returns HTTP 400 idempotency_error; the message gives the accepted range, 1-255 characters.

What to do

  1. Send header Idempotency-Key = new UUID per distinct request.

Dimensions

env: sandbox · plan: any · region: any · account_state: any

Evidence

Probe af:stripe:probe:idempotency-key-too-long (declarative, source)

Observations: none from reporters yet.

Machine access

curl -s https://apifacts.dev/v0/check \
  -H 'content-type: application/json' \
  -d '{"target":{"method":"POST","url":"https://api.stripe.com/v1/customers"},"error":{"status":400,"body_excerpt":"idempotent key length is ### characters long, which is outside accepted lengths. idempotent keys must be #-### characters long. if you'\''re looking for a decent generator, try using a uuid defined by ietf rfc ####."}}'

YAML: facts/stripe/idempotency-key-too-long.yaml

Data: CC BY 4.0 · apifacts registry · This page is generated; edit the YAML, not the page.