Build Audio-Only Consultancy App

Looking for an experienced full-stack mobile app developer/team to build an audio-only paid consultation app similar to Connecto. Tech stack preference: - Flutter frontend - Node.js + TypeScript backend - WebRTC P2P audio calling - Socket.IO - PostgreSQL - Redis - Coturn Core MVP features: - OTP authentication - User & expert profiles - Expert discovery/listing - Wallet & recharge system - Paid audio calls (per-minute billing) - Ratings & reviews - Push notifications - Admin panel Important requirements: - Scalable architecture - Low-cost infrastructure optimization - Clean production-grade code - Strong realtime/WebRTC experience - Experience with payment gateway integration Please share: - Relevant portfolio - Realtime/WebRTC experience - Estimated timeline - Team size - Approximate budget