About UsThe Story

My name is Krzysztof. I’m a tiler. Have been for 30 years. I came from Poland to Hamburg to work with my hands — not to sort receipts every evening.

But that’s exactly what I did for years. Every month the same thing: hunting for invoices, catching up on the trip log, chasing the tax advisor, checking exemption certificates. And still paying too much tax in the end because the data wasn’t complete.

I tried everything — Excel, sevDesk, Lexware, Papierkram. Nothing fit. Everything was built for office people, not craftsmen. None of these programs knew §13b, construction withholding tax, or BRTV working hours.

Craftsmen solve problems. That’s our job. If something doesn’t fit, we make it fit.

Under the SIGMA LUXE technology project, I built BauFin. Not on a drawing board, but on the construction site. Every feature was born from a real problem I had myself.

§13b? Because the tax office took money I could have kept. Trip log? Because I estimated 200 km every month instead of billing correctly. Six languages? Because German construction sites have long been international — Polish, Romanian, Turkish, Croatian — language must not be a barrier.

BauFin is not another accounting editor. It’s a complete system for the craftsman’s daily work.

Invoices, quotes, orders. BRTV time tracking (38h winter / 41h summer). Trip log. Cash book with GoBD-oriented functions and cancellation. Subcontractors with exemption certificate (Freistellungsbescheinigung §48b EStG) and construction withholding tax review. Employees with payroll, Sofortmeldung preparation for DSRV (§28a SGB IV) and separate SOKA-BAU management. Four dedicated portals: customer, accountant, subcontractor and employee. 3-step dunning process (Mahnwesen). Collective invoices (Sammelrechnungen). Receipt scanner with Assistant. E-invoice formats (XRechnung, ZUGFeRD). EÜR generator. DATEV export. Tax prepayments with forecast (ESt/KiSt/GewSt). Security retention §17 VOB/B. Tax audit preparation with GDPdU export. Designed for GoBD-oriented use; setup, working process and procedural documentation remain decisive.

And everything in six languages: German, Polish, English, Romanian, Turkish, Croatian. Because the construction industry is international — and no craftsman should fail at paperwork because of language.

Behind BauFin are two worlds that don’t normally meet:

Krone Baustein e.K. — the construction trade business behind BauFin. The product comes from real construction-site practice, not from an anonymous software idea.

Krzysztof — 30 years of experience on construction sites across Germany. Knows every pain point, every tax office trap, every trip log trick. Didn’t start BauFin as an investor, but as a user who needed it himself.

SIGMA LUXE — the technology project behind BauFin. This is where the software is developed around what construction sites actually need: concrete, lean and without corporate language.