Functional Offline POS System

I operate a service–based company that supplies minerals, offers transportation, and rents out heavy machinery. Field teams frequently work in remote areas with unreliable connectivity, so I need a point-of-sale system that keeps every sale flowing even when the internet drops.

Core requirements
• Runs fully offline, queuing transactions locally and syncing automatically once a connection returns.
• Inventory management to track stock levels for minerals, spare parts, and equipment.
• Customer management that lets staff create or update client profiles on the spot.
• Sales reports I can filter by date, location, service type, or staff member.
• Ability to trigger manual transactions using protocol 201.3 (or an equivalent routine you can recommend) so staff can record hand-written receipts and reconcile them later.

Tech flexibility
I’m open to web-based, desktop, or mobile solutions as long as they stay responsive in the field and run on standard Windows laptops or Android tablets. If you already have a framework that supports service businesses rather than retail menus, that’s a plus.

Deliverables
1. Installable POS application with the features above.
2. Clear setup instructions and user guide for our field teams.
3. Source code or documented build process so we can maintain the system internally.

Indicate the stack you prefer, how you’ll implement the offline data store and sync logic, and any prior projects that show you understand robust offline workflows. I’m ready to start as soon as I see a concise plan and timeline.