Not just imagined. Actually built.
I build apps and tools, mostly because something annoyed me first. Some end up in the App Store, some as open source on GitHub.
A memory for your skincare products. Purchase history, reorders, shelf life and routines across every shop.
Personalised AI picture books for children: describe a character, pick an idea, and every page shows the same hero. Exports as PDF.
Clients, appointments, invoices with SEPA QR code and cash-basis accounts for freelancers and small practices.
Product databases know the big brands. Small makers and purchases from different shops are missing, and your own verdict gets lost over the years.
A personal product memory that works without a complete catalogue. Discovery and trends are left to other platforms.
Your own photo instead of a mandatory catalogue entry, barcode recognition, purchase history, routines, shelves shared among friends.
One web codebase in vanilla JS, mobile later via Capacitor. Supabase in Frankfurt for sign-in, data and access rules.
No trend feed, no discovery algorithm, no ingredient analysis.
Coding agents and I kept repeating the same mistakes that no linter sees: a check that reports green although it measured nothing, for example. Every repeat cost time and tokens.
Every proven bug becomes a fixed rule. Every rule needs a broken and a healthy sample, or it does not load. “Not measured” is a result of its own and never counts as passed.
If many people share their bugs as rules, none happens twice to anyone. That is what ruttla-hub with its reviewed rule packs is for. Checks run without AI, often before the bug is even in the code.
Rules as data, run by a Rust engine with linear-time patterns. Python only where a pattern is not enough.
Ruttla runs over the changes before every commit. On top come checks of its own: brand from one source, no text bypassing the catalogue, no product image without a source.
No language model, no network and no telemetry while checking. The code under test is read, never executed.
I am Johannes Hehl, and I build the products behind lupfa. My background joins technical plant engineering and systems operation with software development.
Most projects start with irritation. Henga exists because NAS connections on the Mac kept hanging, and the store apps for it cost money or sell every feature separately. Lugga, because Synology Photos only runs in the browser on the Mac, and the yearly photo book turned into a test of patience there. Ruttla, because I did not want to hunt the same bugs three times.
lupfa. from Southern German “lupfen”: to lift, to raise.
Tell me what it's about. Two or three sentences are enough. I reply personally.