Four POS systems, taken apart.
A coordinated reverse-engineering study of four point-of-sale platforms — to learn the craft, find what's hard, and design sunpos, a POS Mipos could build.
Four agent sessions each tore down a live POS back-office — read-only, from the outside — while a coordinator compiled, cross-checked, and stress-tested the findings into a build proposal and a working, verified data-model prototype. This wiki is the full compilation: click any system for its complete teardown (tech stack, architecture, feature list, data model, site map), or jump to the comparison and the sunpos proposal.
Colmo ✓Keivi ✓Loyverse ✓FeedMe ✓sunpos · 56-table schema verified
✅ sunpos now runs as a live system — a back-office admin and a POS terminal sharing one Cloudflare D1 database (the 56-table schema below). Add a product in the admin → it appears in the POS. See the live system.
The four systems
Each page renders the session's full teardown — stack, architecture, every feature, the reverse-engineered data model, and the route map.
Colmo
Multi-outlet F&B POS on a Backend-as-a-Service stack (Svelte + Firebase + S3-as-DB). The lean-cloud reference and a data-access cautionary tale.
Keivi / KiotViet
Vietnam's #1 SME POS, KKR-funded, 15 yrs. AngularJS + Kendo over .NET microservices, native MyInvois. The parity benchmark.
Loyverse
1M+ merchants, bootstrapped, freemium. Clean UX, open API, native offline apps. The UX + API reference.
FeedMe
Modern Vue3 micro-frontend restaurant OS — 24 MFEs / 12 domains, NestJS/Mongo + BI warehouse. The build blueprint.
Synthesis
Comparison
All four mapped onto the axes that decide a POS build: catalog model, offline sync, fiscal, payments, integrations, hardware.
sunpos proposal
What Mipos should actually build, why, and in what order — plus the stack, the phased plan, and the open decisions.
Prototype
The pod-built data model — design notes, every modelling decision traced to a teardown, and the 7-migration stack.
Service design
How the schema actually runs: data-access isolation, the order engine, the fiscal service, and the event-outbox platform.
Live POS terminal ↗
The working terminal UI — tap a tile, configure modifiers, split tender, see the receipt + kitchen ticket. Rings against the schema.
The one-line lesson: the back-office CRUD everyone can see is the easy 20%. Every POS — regardless of stack or age — lives or dies on the same five hard problems below the surface: the catalog/order data model, offline-first sync, fiscal compliance, payments, and the integration long-tail.
POS R&D Wiki · compiled by the D45 coordinator + the four teardown sessions · Mipos · 2026-06-12 · read-only competitive study, no data mutated on any live system.