PhoneWhat it triggersThe softwareFaxWhat a fax costsVerified fax lines

Phone service over WiFi

The software is easy. The stacks are mature, permissively licensed and actively maintained, and you could have members calling each other this month. The software is not the hard part — and the hard part is invisible from the code.

The line that decides everything: the moment a service carries calls to or from ordinary phone numbers, you are an interconnected VoIP provider in the FCC's sense. E911 with a registered caller location. FCC registration and Form 499-A. Universal Service Fund contributions on interstate revenue. CALEA lawful intercept. CPNI rules with an annual certification. State registration and 911 fee remittance in some states. App-to-app calling triggers none of it.

The build order

1

App-to-app voice/video with LiveKit + coturn

no carrier obligations

ships without touching the regulatory question at all, and coturn is what makes it actually connect for the ~20% of users behind symmetric NAT

2

Live audio with MediaMTX or Owncast, pointed at the existing radio reader

none

radio.mjs already POINTS at broadcasters' own streams and never rehosts — this adds the ability to originate OUR OWN stream without changing that posture for theirs

3

Real numbers by RESELLING from a licensed carrier

carrier holds E911, 499-A, USF, CALEA, CPNI

⭐ the same carriers already priced for fax in doc-services.mjs — one account, both products, and the regulatory burden stays with them

4

Own interconnected VoIP service

E911, FCC registration, USF, CALEA, CPNI, state filings

⚠️ only if volume ever justifies it. E911 alone is a programme, not a feature.

Why not just get numbers

You can — by reselling from a licensed carrier. Telnyx, Bandwidth and similar already hold the registrations and run the E911 plumbing, and a white-label arrangement leaves the regulatory burden with them. It costs margin, and it is how nearly every small phone app actually ships. ⭐ The same carriers are already priced for fax — one account, both products.

→ the three tiers, with the obligations listed

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.