Matrix homeserver — messaging + VoIP signalling · Python · AGPL-3.0
Federated messaging with calling built on the same WebRTC. ⚠️ AGPL-3.0.
Last push 2026-09-07 · 4589 stars at survey time. github.com/element-hq/synapse
Engineering and regulatory orientation, not legal advice. The FCC obligations named here are real and enforced; confirm your own position with counsel before carrying a single call to a phone number.