Phone Number Friend Finder

I want an application whose single purpose is to let a user locate a friend simply by entering—or even initiating a call to—their phone number. The flow should be friction-free: the user types or taps a number, the system verifies permission from the friend’s device, and the current location is returned on an interactive map.

I’m flexible on implementation (mobile-first would be ideal, but a responsive web app is fine if it delivers the same smooth experience). Whichever route you choose, priority one is reliable phone-number tracking that complies with local privacy laws and obtains explicit opt-in from every party involved.

Key expectations
• Real-time location lookup triggered by phone number
• Clear permission and consent handling for both caller and callee
• Map display with refreshing coordinates and last-seen timestamp
• Clean, well-commented code and a short setup guide so I can spin up the project myself

If you have prior experience working with telco APIs, number-based geolocation, or integrating services like Twilio, Nexmo, or similar, please mention it. I’m happy to answer any technical questions before you start.