API errors

Too many requests (burst rate limit)

You sent requests faster than the burst rate limit allows. This is a short-term throttle, separate from your document quota — the quota is unaffected.

Error type

https://normbill.com/docs/errors/rate-limited

HTTP status

429

Common causes

• A spike of requests under one API key exceeded the per-key burst limit.
• Many requests from one client IP exceeded the per-IP backstop (which also catches unauthenticated or rotating-token traffic).
• A retry loop without backoff is hammering the endpoint.

How to fix it

• Slow down and retry after a short pause — the burst allowance refills continuously.
• Add exponential backoff to your client and avoid tight retry loops.
• Spread bulk work out over time instead of firing every request at once.
• Note this is not your document allowance: quota-exceeded is the separate per-billing-period limit.

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, generate-failure-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.