Booking API A production-style appointment booking REST API with conflict detection — built with NestJS, TypeScript, PostgreSQL and Prisma. NestJS TypeScript PostgreSQL Prisma Swagger 🎯 Problem Businesses that take appointments (clinics, salons, consultants) constantly deal with double bookings when scheduling is manual. This API solves that: it validates every booking request and automatically rejects any appointment that overlaps with an existing confirmed one.