POST /v1/einvoice/validate · 1 cent per operation

Validate XRechnung / ZUGFeRD (KoSIT)

Full rule check of XRechnung 3.0 and EN 16931 invoices (incl. ZUGFeRD/Factur-X EN 16931) with the official KoSIT validator: every error with its rule number, or a PDF report.

Try it

curl -X POST https://api.bigapi.dev/v1/einvoice/validate -H 'Authorization: Bearer $KEY' -F 'file=@xrechnung.xml'

New keys come with 100 free operations, no signup: curl -X POST https://api.bigapi.dev/v1/keys. Failed calls cost nothing.

Parameters

Name	Meaning
`file` required	E-invoice as XML (XRechnung UBL or CII, ZUGFeRD/Factur-X XML) or as PDF with an embedded invoice XML (ZUGFeRD, Factur-X, XRechnung hybrid).
`output`	json lists errors, warnings and notes; pdf returns a printable validation report. Allowed: `json`, `pdf` Default: "json"
`lang`	Language of the PDF report. Allowed: `de`, `en` Default: "de"

Result and price

1¢ · 1 cent per operation

Returns application/json | application/pdf. Response headers carry the cost (X-BigAPI-Cost) and notes about your input (X-BigAPI-Warnings).

Good to know

Three results: valid, invalid, or not_checked. not_checked means the official rules do not cover this profile (MINIMUM, BASIC WL, ZUGFeRD 1.0); it is never reported as green.

Errors your agent should handle

`400 not_an_einvoice`	Not an invoice in UBL or CII, or XML with a DOCTYPE.
`422 no_einvoice_in_pdf`	A plain PDF without embedded invoice XML; in Germany that is not an e-invoice.

From an agent (MCP)

Connect BiGapi as an MCP server: https://api.bigapi.dev/mcp (hosted) or npx -y @bigapi/mcp (local). Then ask in plain words; the agent finds einvoice_validate on its own.

Is this XRechnung valid? If not, what do I have to fix?

More: all guides · API docs · llms.txt