POS System
The problem
I wanted to know exactly how a point-of-sale system works end to end — with no framework hiding the details.
What I built
A POS built on vanilla Node.js and a raw HTTP server, persisting to SQLite, with hand-rolled routing, parameterized SQL, an input sanitizer, a path-traversal guard, a per-IP rate limiter, scheduled backups, an EAN-13 generator and receipt printing.
The result
A working, from-scratch POS that demystified the full request-to-receipt path. Checkout was later made atomic and priced from the catalogue rather than the request, with tests, and CI added in 2026.