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Case Study2021 - 2022
Point of Sale (POS)
A retail cash register application that operates offline and automatically syncs local transactions back to the cloud when internet returns.
Role
Full Stack Engineer
Sector
Inventory System
pos://register-lane-02
MAKSUDS RETAIL
1x Mocha Coffee180 BDT
2x Croissant240 BDT
TOTAL DUE420 BDT
OFFLINE MODECached: 3 txns
The Challenge
- Synchronizing multi-outlet transactions with central inventory without data loss.
- Keeping transaction latency below 100ms on low-spec client hardware.
- Directly interfacing with POS receipt printers and barcode scanners on the browser client.
Our Solution
- Built a local-first browser IndexedDB structure that queues sync events.
- Optimized React state renders and query paths to run efficiently on low-spec PCs.
- Designed a modular client-side printer driver communicating via native browser print APIs.
Measured Impact
"Deployed across dozens of checkout lanes, maintaining 99.9% inventory sync accuracy even during local internet dropouts."
System Reliability Verified