Most software pulls work toward you. I build software that pushes it away. Nothing I build should need me. It needs you only once, where the law says a person must decide.
An operations layer for German tax practices. It sits in the mail flow. Post arrives and is read and classified. The figures are computed deterministically and traced to the paragraph of law that produced them. A reply is drafted on the firm's letterhead, and the Berufsträger receives one email: the draft, the figures, a confidence score, and gives Freigabe. It files, it logs, it watches the Fristen.
Nothing to open, nothing to learn, nothing new in the office. It works in the background, and the routine stops reaching desks.
Every figure is computed from the law, never by a model. Nothing leaves the building. § 203 permits no other architecture.
It prepares and it proves. It does not sign. The Berufsträger does.
The compute layer. The calculators are generated from the Bundesfinanzministerium's own published pseudocode, not transcribed by hand, because hand transcription gets the decimals wrong. Exact decimal arithmetic, no floating point. Every figure carries its paragraph and the hash of the source it came from. Checked against an independently written implementation across 25 statutory years: 100.000 field comparisons, zero deviations, in value and in decimal places.
Specified in full, not yet built: the mail loop and the channels, the Fristen register, the Freigabe routing, the revisionssichere archive, the operator dashboard.
The same architecture at the scale of one practice. It reads a DATEV export and finds money left behind. It runs entirely on the advisor's own machine, with zero outbound connections, checkable in the network tab. The advisor approves and files. staedy never files.
Complete, and sold to nobody. One practice cannot justify the layer beneath it. Build it once, and every practice that joins runs on it: the tenth costs less to integrate than the ninth. That is how a group grows faster than it hires.
Everything before led here, and I have the school fees to prove it. I can architect and build the whole chain, because I have sat in every seat along it.