The technology stack can vary based on your needs and requirements.
However, if you decide to build a video chat app from scratch, in
general, consider:
Data protection and encryptions (AES-256 and HMAC-SHA256
protocols, HIPAA protocol for telehealth solutions, GDPR, etc.)
Video protocols (WebRTC, VidRTC, Twilio, FFMPEG, GStreamer, Janus,
Pion, etc.)
Mediasoup
AWS
GraphQL