- RoleMobile & backend engineer
- TookOngoing
- Year2026
- Built with
- Flutter
- Dart
- Drift
- Supabase
- PostgreSQL
- Edge Functions
- RLS
- 69Row-level security policies
- 38Tables
- OfflineSells without a signal
What was wrong
Reps sell from vans, warehouses and shop counters — places where connectivity is not a given. A POS that pauses for the network is a POS that loses the sale, and money moving through cash drawers, wallets and instalments has to reconcile exactly at the end of the day regardless.
What I did
The mobile app writes to a local Drift database first and queues every action in an idempotent outbox, so a sale completes whether the network is there or not and syncing twice never double-counts. The server is the authority: 38 tables, 82 functions and 69 row-level-security policies enforce who may see which warehouse, which treasury and which customer — in the database, not in the interface.
What changed
Selling no longer depends on the signal, and the day closes on a Z-report that ties every invoice, collection and expense back to a treasury. Because the rules live in the database, a new role is a permission row rather than a release.
What is inside
A POS that works offline
The sale is written locally first and waits in an idempotent outbox, so no amount of re-syncing can count it twice.
Treasuries and a working day
Cash, mobile wallets and sub-treasuries, with the day opened, banked and closed on a Z-report that ties every movement to its treasury.
Warehouses, stock counts and purchases
Inventory, customers, purchases, advances and stock counts, with Excel import for anyone starting from records that already exist.
Permissions live in the database
69 row-level-security policies decide who sees which warehouse and which treasury — the interface does not hide the data, the database never hands it over.
Reports, audit trail and backups
Full reporting and an audit record for every movement, with automatic backups to Google Drive.
One codebase, phone and web
The rep app and the admin dashboard are both Flutter from a single codebase, over Supabase.
Abo Dola Studio
Still reading?
Then we should probably talk. Thirty minutes, free, no slide deck. Worst case you leave with a second opinion.