Calculate take-home pay across 67 countries. Rules hard-coded from official government sources — not a third-party API wrapper. Covers Europe, Americas, Asia, Middle East, Africa & Oceania. Full social insurance modeling: FICA (US), NI (UK), CPF (Singapore), pension (Japan) and more. Side-by-side country comparison, shareable URLs, dark mode, and a deployable REST API with auth and rate limiting. Built in TypeScript. 79 unit tests. Available for acquisition.