API errors

Invalid request body

The JSON body of your request does not match the documented schema. The invoice was not processed — validation never started.

Error type

https://normbill.com/docs/errors/invalid-request

HTTP status

400

Common causes

• A required field is missing (for example invoice.number, invoice.issue_date, seller.address.country or lines[].unit_price).
• A field has the wrong type (a number sent as a string, a date not in YYYY-MM-DD format).
• An unknown field was sent — the request schema is strict and rejects keys it does not know.
• The body is not valid JSON, or the Content-Type header is missing.

How to fix it

• Read the errors array in the response: each entry carries the JSON path of the offending field and a message.
• Compare your payload against the request schema in the API reference (https://api.normbill.com/docs) or the example on the docs start page.
• Field names are snake_case (unit_price, issue_date, buyer_reference) — camelCase variants are rejected as unknown keys.

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.