Medrilo
A Laravel API on MySQL, with an app built in React and TypeScript. Capacitor wraps it for Android, so the phone and the web share one codebase.
Evencup
Flutter, for iPhone and Android from one codebase. Its core is a deterministic calculation engine with its own suite of automated test scenarios.
RBCS and this website
Plain PHP and MySQL with server-rendered pages and a little vanilla JavaScript. There is no framework and no build step, so they can run for years on ordinary shared hosting. I wrote about that choice in In praise of boring technology.
How I work
Automated tests for the parts that matter most, separate records for anything that must not quietly change, and interfaces in the language of the person using them.