Pricing

What a commercial Klarfakt licence costs, what it covers, and the rule pack update commitment.

Most people reading this owe nothing. Klarfakt is free unless your organisation turns over more than €1,000,000 a year, free at any size inside OSI-licensed open source, and free always for evaluation, development, CI and internal testing.

If that covers you, stop here and go back to the README.

Commercial licence

For production use above that threshold. Per organisation per year, excluding VAT where applicable.

No metering, ever. Validation happens in your process, on your hardware. Klarfakt cannot count your invoices and is not built to.

Support

Email, and in practice you will usually hear back within a working day. That is what happens rather than a number in a contract: an hours-and-minutes commitment is worth having when there is a rota behind it, and a promise nobody can keep on a bad week is worth less than none.

What is committed is in the section above — rule pack updates for the term, every version released during it kept permanently, and the Change Date that cannot be extended. Those hold whatever any given week looks like.

Extended adds a named contact and puts your issues ahead of the backlog.

What a licence keeps

A licence covers every version released during its term, permanently. Licence today, stop renewing in a year, and you keep the right to run everything published in that year, in production, indefinitely. What lapses is new versions and support, not the software already in your pipeline.

You should not have to bet an invoice pipeline on anyone’s continued attention. What you licensed keeps working whatever happens next, and the Change Date is a ceiling that cannot be moved — not a promise that depends on this project still being here to keep it.

Founding customers

The first three commercial licences are €390 a year, held at that price for three years, in exchange for permission to name the customer and an honest conversation about what is missing. Three people saying what is wrong with this is worth more right now than ten silent renewals.

Rule packs

This is the part being paid for. CEN, OpenPEPPOL and KoSIT each publish roughly twice a year, and a national CIUS release can change the verdict on invoices that passed last month.

The commitment: a new pack version within 30 days of its upstream release, with a report of every corpus verdict that changed. Bumps are never silent — tools/reference-diff.py compares every verdict against KoSIT’s own validator on each run and the build fails on a disagreement that has not been written down.

Thirty days is a commitment about the routine releases. A new major profile — XRechnung 4.0 for the revised standard, when it appears — brings new syntax bindings and new schemas with it, and the reference validator has to support it before the comparison can stay green. That is a different class of work and it would be dishonest to price it as the same promise: what the 2026 revision means for a licence.

Supported frameworks

Every .NET version Microsoft still supports, plus the current LTS. Today that is net8.0 and net10.0, both tested on every commit. A framework is dropped only after Microsoft ends support for it, announced one minor version in advance.

Buying

Email licensing@klarfakt.dev with the organisation name and the tier. Back comes an invoice and a licence certificate naming the organisation. No sales call, no procurement portal, no per-seat audit.

The terms are written down and readable in ten minutes: commercial licence agreement. Worth reading clause 3 before choosing a tier — shipping Klarfakt inside a product you sell is the whole difference between Standard and Extended.

Unsure whether the threshold applies, or whether a particular use counts as production? Ask. A straight answer costs one email.

If the project stops

Every version of Klarfakt becomes Apache 2.0 four years after it is published. The licence sets that as a ceiling and it cannot be extended or revoked — version 1.x converts on 2030-09-04, and later versions carry their own dates.

So the worst case for a customer is ending up with permanently free open-source software, on a schedule that is written down rather than promised.