Senior Full-Stack / Integration Engineer Needed

Experienced Senior Full-Stack/Integration Engineer required to finalize LETA24, a South African multi-service Super App. The platform aggregates rides, fuel delivery, food, groceries, travel, health, home services, shopping, courier, payments, communities, AI concierge and rewards. You will audit and preserve the existing mobile and web codebases, fix incomplete or broken flows, complete authentication and social logins, integrate external providers, validate AI concierge, execute exhaustive end-to-end QA, ensure security, finalize payment/BaaS integrations, and prepare production deployments. Deliverables: comprehensive audit inventory, resolved critical bugs, completed integrations, full regression testing, production-ready builds, documentation and handover within a three-week timeframe. Must be proficient with React/Next.js, React Native, Node/NestJS or FastAPI, PostgreSQL/MongoDB, OAuth, payment gateways, maps and webhooks. Strong debugging, integration and QA mindset required. Availability for 30–40 hours/week, daily progress updates and adherence to existing architecture is essential. Budget: $10/hr; initial engagement three weeks with potential extension. www.leta24.com