Full-Stack Developer for Voice AI SaaS

Build a commercial SaaS web application for language learners with a real-time conversational Voice AI agent. Users should create accounts, speak naturally through their microphone, receive real-time voice responses, and complete structured speaking sessions. The system should support speech-to-text, text-to-speech, low-latency conversations, session timing, conversation history, progress tracking, and AI-generated feedback. You will also build a student dashboard, secure authentication, subscription and access management, an admin dashboard, database integration, and a responsive mobile-friendly interface. Please share examples of similar Voice AI or conversational AI applications you have built.