OrionApps blog

Notes from building small-shop software

Engineering write-ups from the team behind Orion POS and OneTill.

Engineering

Building an offline-first POS app for Android

How we built OneTill, a free offline POS app for Android: integer money maths, a label printer that ignored text commands, and a billing bug that looked like Google's.

November 13, 2026 · 5 min read