API errors

Idempotency key reused with a different body

This Idempotency-Key was already used for a different request body within its 24-hour validity window. Keys pin one exact request; the mismatched request was rejected and nothing was consumed.

Error type

https://normbill.com/docs/errors/idempotency-key-reuse

HTTP status

422

Common causes

• The same key was reused for a different invoice.
• The request body was modified between the original attempt and the retry (even a single field).

How to fix it

• Generate a fresh key for every distinct invoice or payload.
• Reuse a key only to retry the byte-identical request — that is what makes retries safe.

The error response format

Every non-2xx response from the API is an RFC 9457 problem-details body (application/problem+json) with at least type, title, status and detail. The type URL links back to this reference.

All error slugs: invalid-request, bad-request, payload-too-large, unauthorized, validation-failed, unparseable-document, plan-limit, quota-exceeded, rate-limited, overage-cap-reached, validate-fair-use, idempotency-key-invalid, idempotency-key-reuse, idempotency-conflict, pdf-unavailable, validator-unavailable, not-ready. Still stuck? Email support@normbill.com or start at the docs overview.