MVP development Saas

MVP build for a digital loyalty app for local SMBs (retail, food, services) with a Consumer app + vendor dashboard + basic admin backend. Small pilot launch, one city. Fixed-scope MVP. Full spec shared under NDA with shortlisted candidates only. What We're Building (high level — full detail under NDA) Consumer app: phone-number login (OTP), digital wallet of loyalty cards, QR code for in-store redemption Vendor dashboard: business onboarding, a builder tool to configure reward programs, QR scanner for staff, basic usage analytics Multiple configurable reward mechanics (points, cashback, memberships, etc.) — specifics under NDA Offline-first requirement, hard constraint: the in-store QR scanner must function with zero/unreliable connectivity and sync automatically once back online with zero data loss. This is the core technical challenge of the build — please speak directly to relevant experience. Automated customer messaging via an official WhatsApp Business API integration (managed provider, not an unofficial library) Basic admin backend for platform oversight Tech Stack Backend/DB: Supabase (Postgres) Hosting: Vercel Mobile: React Native or equivalent cross-platform (open to your recommendation) Payments: gateway integration, details under NDA What We Need From You Full-stack, able to own both frontend and backend architecture Direct experience with offline-first app design — local caching, sync-on-reconnect, conflict resolution. This is the single hardest problem in the build; address it specifically in your application. Experience with QR-based transactional flows (POS-adjacent experience a strong plus) Able to work independently with a non-technical founder — translating requirements into technical decisions, not just executing a fixed spec Bonus: WhatsApp Business API integration experience, South Asian/emerging-market app experience Engagement Terms Fixed-price milestone-based (preferred) or hourly — open to discuss Paid contract role — not an equity engagement NDA required before full spec/scope is shared To Apply Include: Relevant offline-first or POS/transactional work (links/examples) Your proposed approach to the offline-sync problem, 2-3 sentences Timeline estimate for an MVP of this general scope Day rate or fixed-price range Shortlisted candidates receive an NDA and full technical spec before final scoping.