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Disposable phone numbers (roadmap)

What it will be

Section titled “What it will be”

On-demand phone numbers the user can spin up, bind to a specific service, and throw away when the service starts spamming. Unlike prepaid burner SIMs, these live entirely in the app:

  • Numbers provisioned from Twilio / Telnyx / Bandwidth (SIP providers).
  • Incoming voice forwards to the user’s real number, OR stays in the app as voicemail-only.
  • Incoming SMS stays in the app OR forwards to the user’s real number as a push notification.
  • Outbound calls and texts use the disposable number as caller ID.

Provider selection

Section titled “Provider selection”
  • Telnyx — cheapest per-number, best programmable-routing API. Likely pick.
  • Twilio — most documentation, widest coverage, priciest. Possible for non-US.
  • Bandwidth — cleanest compliance story (CNAM, E911). Use if we need enterprise-grade posture later.

Starting with Telnyx for the proof of concept.

Regulatory reality

Section titled “Regulatory reality”

Every country has its own rules:

  • US: E911 routing, CNAM registration, number portability. Non-trivial but solved by the SIP partner.
  • EU: GDPR on call/SMS metadata. If we log anything, we must let users export and delete. Design assumes encryption at rest with user-held keys so we cannot decrypt without cooperation.
  • Other: Ship US + EU first; everything else is “coming soon.”

Privacy architecture

Section titled “Privacy architecture”

This is the trickiest module in the roadmap. A forwarding service inherently sees the phone number you forwarded from and the one you forwarded to. That metadata is a liability.

Design principles:

  • Metadata encrypted at rest under a key the user controls. The server can route a live event (incoming SMS → forward to device X) because the event payload contains the user’s routing key, which is decryptable only at the edge of the event. The persisted logs are ciphertext.
  • No call/SMS content stored on our servers. Voice + SMS is proxied in-session; we keep “number Y rang at timestamp Z” ciphertext and nothing else.
  • Honest retention: 30 days of encrypted metadata by default; user can shorten or disable.

Pricing model

Section titled “Pricing model”

Candidate:

  • Sovereign tier includes 3 numbers + an inclusive allowance of forwarded minutes and SMS.
  • Overage: cost-plus from SIP-partner invoices, no hidden margin.
  • Number rental is per-month ($1-2 typically for US, more for international).

Locked in when the product is closer to ship.

Target timeline

Section titled “Target timeline”

Not committed. Last of the five roadmap modules because of regulatory depth + commercial risk. Earliest: 6 months out.

Section titled “Related”