Prototype
This tool is a prototype, developed in-house in Rust and WebAssembly (WASI) — the very same technology that runs this website.
Back to the e-invoicing obligation
E-invoice
Check e-invoice
Upload an XRechnung or ZUGFeRD invoice, or paste the XML — we check it against EN 16931 and the KoSIT rules and show you every finding in plain language.
No claim to correctness
This check is not legally binding and makes no claim to being correct or complete. Use is at your own responsibility; a passing run is no substitute for professional sign-off.
Bit-identical to KoSIT — yet still a prototype
In our tests the check produces a bit-identical result to the official KoSIT validation tool (255 of 255 sample documents). That is a solid state — it nonetheless remains a prototype.
Data protection, enforced by design
Every upload spins up a fresh, rightless WASI component — no file system, no network access — which is discarded afterwards. Nothing from the submitted file is stored or logged — no traces remain. This is enforced technically, not merely claimed.
Malicious input hits a dead end
A compromised PDF or a manipulated XML can do nothing here: every check runs in a fresh, rightless WASI component that is destroyed afterwards — with no file system and no network (wasi:sockets is not even imported). XXE, SSRF or exfiltrating files are therefore technically impossible, not merely forbidden. Even an exploit would stay trapped inside the WASM sandbox — no access to the host, no RCE — and is gone the instant the instance is discarded.
Check e-invoice
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Validator as open source
We are glad to share this validator as open source — with all liability excluded. If you are interested, write to us and we will get back to you with the details.
Whether the obligation already applies to your business, which formats count and what applies on receipt is set out in our overview. To the e-invoicing obligation