CONTEXT
Built for street vendors and small merchants to run fast sales in low-connectivity environments. Traditional paper logs cause queues and lost records during peak hours.
02 / PRODUCT
Caixa da Feira
Offline-first PWA for sales in pop-up markets and itinerant operations.
PROJECT OVERVIEW
Technical highlights
A practical sales and checkout management system built for dynamic physical locations and event operations. Replaces manual records with a fast PWA featuring products, cart, payment methods, sales history, reports, CSV export, and cloud sync.
- Installable app
- PWA
- Local-first sales flow
- Offline
- Exportable reports
- CSV
CASE STUDY
From context to outcome
TECHNICAL DECISIONS
Offline-First Architecture
Sales logging, inventory updates, and cash register operations work without internet. Data persists locally via IndexedDB.
Resilient Synchronization
Sync queue with automatic retry detects connection recovery and merges data without blocking transactions.
High-Speed Interface
Touch layout optimized for basic smartphones, featuring large hit targets, preset amounts, and auto change calculation.
RESULTS
Validated in production with continuous offline sales flow, reducing checkout time per customer and ensuring accurate end-of-day register closing.