E-invoicing is becoming mandatory across the EU. If it reaches your business, this is what it means and how beliq handles it. beliq is one integration for the whole e-invoice lifecycle: generate the file, validate it against the authority’s own rules, and, next, deliver it over the right network. Generate and validate are live today. The video is the short version; the detail is below.
What an e-invoice is
An e-invoice is an invoice a machine can read. Not a scan or a picture of a document, but structured data, laid out to a defined schema, that the receiving system (including a tax authority’s) can parse and check on its own. That structured data can travel as a standalone XML file, or it can be carried inside a PDF, so one document is human-readable and machine-readable at the same time. Factur-X and ZUGFeRD are exactly that: a normal-looking PDF with the structured invoice embedded inside it.
Across the EU this is turning from good practice into law. One country after another is setting dates from which an invoice has to carry that structured data to be valid, so a plain PDF or a paper copy on its own stops being enough. The details differ between countries, but they build on a common core, the European standard EN 16931.
The authority sets the rules
What counts as a valid invoice is not a matter of interpretation. Each tax authority publishes the definition itself, as files a computer can run: XML schemas for the structure, Schematron rule sets for the business rules, released and maintained by the bodies that own them, CEN for the shared European core and each country’s tax authority for its national rules. beliq does not keep its own reading of those rules. It runs the published files directly, so a valid result means your invoice met the authority’s own definition, not ours. Where an authority publishes only a schema and no machine-readable business rules, beliq checks against that schema and labels the result as such, so a verdict never claims more than the authority’s own files support. That is what compliant by design comes down to.
You can’t argue with a tax authority. So beliq doesn’t. It runs theirs.
And you can check that it did
Every result names the rule sets it ran, their versions, and includes a hash of each one. A hash is a fingerprint for a file: run the file through the same calculation and you always get the same short string back, and change anything in the file and that string comes out completely different. So you can take the hash from a result and confirm for yourself that the rules beliq ran are the exact ones it pins, and that they have not changed since you last looked. The verifying-hashes guide has the steps.
The upkeep is the hard part
The rules do not sit still. Every format beliq carries has its own schema and country rule sets, each revised on its own schedule by the body responsible for it. beliq pins an exact version of every artifact and re-checks it against the source on a published cadence, so a change at the authority becomes a version update on our side instead of a rejected invoice on yours. Which formats and countries beliq covers is kept current on the coverage page.
JSON in, invoice out
Producing an invoice works the same way in reverse. Send a JSON description of the invoice to our REST API, and beliq returns a finished file: the XML, or a Factur-X or ZUGFeRD PDF with the XML embedded and the whole thing validated to PDF/A-3b. The rules that check an invoice are the same ones that shape the one beliq builds, so the output is already valid when you receive it. beliq builds the file and checks it today; sending it, to your customer or onto a network, goes through the access point or portal you already trust. Managed delivery is what beliq builds next: automatic routing across certified EU networks, chosen per destination. It is coming soon, and until it ships that step stays with you.
It stays in the EU
An invoice is business data, and it runs through beliq’s systems whether you validate or generate. All of it runs inside the EU, on Hetzner. Nothing crosses to the US. The Trust Center lists every subprocessor, what it does, and where it is based.
Where that leaves you
That is the shape of it: rules from the authorities themselves, results you can verify, the same output every time, and everything inside the EU. The part we care about most is the part you can check yourself. The validator is free and the API reference is open; the best way to judge it is a real invoice.