Add Booking-Based Chat & Call Feature to Xplooreze

We are looking for an experienced developer/team to integrate a secure, booking-based chat and audio/video calling feature into our existing tutoring website, Xplooreze.

What we need
Chat linked to each booking/session — not a general inbox
Text messages + image/file attachments
Audio and video calls directly inside the browser
No phone numbers, emails, or personal contact details shared
Users see only an approved display name/alias
Online / waiting status so users know if the other person has joined
Communication opens around 30 minutes before the session and closes/archives a few hours after it ends
Notifications for new messages and incoming calls
Integration with our existing user, tutor/student, and booking system
Responsive for desktop and mobile browsers
Optional features
Admin-configurable number of participants (1-to-1 or group sessions)
Screen sharing
Chat/call history and logs for support or dispute resolution
Please include in your proposal
Recommended technology/SDK and why
Timeline and fixed cost
Any recurring third-party costs
Examples of similar chat/video-call features you have built

Please start your proposal with "XPLOOREZE CHAT" to confirm you have read the requirements.

This is for an existing website, not a mobile app. We prefer someone who can understand our current booking flow and recommend a secure, scalable solution.