I’m putting together a high-performance booking layer for a multi-tenant hospital & clinic platform and need a specialist to build the core REST/SignalR API from the ground up. The service must push live slot updates via Signal R, keep latency low with Redis caching, and protect every endpoint behind JWT and role-based policies. The API will feed both our web dashboard and Flutter/iOS/Android apps, so clean, well-documented Swagger/OpenAPI specs are essential. Typical flows include searching available doctors, confirming appointments, rescheduling, or cancelling—each action triggering automated promo messages as well as an AI-powered auto-reply that immediately answers common patient questions. Interactive messaging should go beyond simple “yes/no” responses. In-thread features have to cover: • autoNotifications (appointment confirmations, reminders, follow-ups) • real-time wait-time alerts pulled from our queue engine • contextual tips based on the patient’s stored medical history (FHIR-compatible format) Deliverables 1. Production-ready .NET (C#) solution with layered architecture (domain, application, infrastructure) 2. Signal R hub for live slot broadcasts and chat-style patient replies 3. Redis integration (cache aside pattern) with sensible expiry keys for schedules and doctor metadata 4. Secure JWT auth with refresh tokens, role scopes, and unit tests covering auth paths 5. Postman/Swagger collection illustrating all endpoints and example payloads 6. Read-me & deployment script (Docker-compose or Helm chart) for staging Acceptance Criteria • Average response time under 150 ms for search/booking endpoints under a 500 rps load • Real-time updates visible across at least two simultaneous client connections in <1 s • 100 % branch-covered tests for authentication and booking lifecycle • Automated CI run proves container builds, migrations, and seed data execute without errors If you’ve built healthcare or high-traffic booking systems before and can show measurable performance gains, I’d love to see your approach.