Sapplify is a software studio in Slovakia, founded in October 2024. We build small products that do one thing properly: a family of everyday apps for the things people actually keep track of, a sudoku game, and euinvoice, a platform for EU e-invoicing. A second game is in development. The apps are one system rather than a collection. They share a single Sapplify account and free sync, so what you set up in one carries to the next, and they share a design language, so learning one teaches you the rest. They are local first. Every app works before you sign in, and keeps working if you never do. The account is opt-in, sync is opt-in, and sync costs nothing. euinvoice is the studio's business product, built for the e-invoicing mandates arriving across the EU country by country. It generates compliant invoices with reverse charge handling and Factur-X / EN 16931 export. It produces the documents; it does not transmit them. Small is the method, not a limitation. Range comes from making more products, not from growing any one of them into something it was not meant to be. sapplify.com