Why I'm trying to kill the prepaid international calling card

Hi IH 👋

I'm Ivan, solo founder of TwinPhone. This is the first post on this page so I'll keep it short.

What TwinPhone is

A pay-as-you-go international dialer that runs entirely in your browser. Open the site, sign in, dial. Calls go through real carrier SIP trunks (Twilio + Telnyx, running in parallel with auto-failover) at $0.02/min to landlines and $0.08/min to mobiles across 180+ countries. No app, no SIM, no monthly fee, no contract. Pay only per second, balance never expires.

Why I built it

My family still uses prepaid international calling cards to call relatives back home — the kind you scratch off a number and dial through some 1-800 gateway. They pay $0.30 to $0.80 per minute and lose the unused balance every 90 days.

It's 2026. Modern WebRTC plus competitive SIP wholesale should make that cost a tenth of what it is. There is no technical reason international calling has stayed expensive — only commercial reasons. Carriers profit from confusion, expats pay the tax.

So I built TwinPhone to test whether browser-WebRTC could deliver carrier-quality voice at wholesale prices, without any of the usual baggage (app downloads, contracts, login lock-ins, hidden fees).

The answer turned out to be yes, but with a catch — getting voice quality and connection reliability right took way more engineering than I expected. SIP trunks lie about their CDRs (more on that in a future post), media planes fail silently behind successful signaling, and a healthy chunk of WebRTC calls were being marked "completed" with zero actual audio. Fixing all of that has been the bulk of the work for the last two months.

Where we are right now

- 180+ destinations with per-second billing

- Virtual numbers + SMS forwarding

- 5 languages (English, German, French, Spanish, Russian)

- Single-founder, fully bootstrapped, no employees, no funding

Early traction is small and honest — handful of users per day, mostly word-of-mouth in expat Telegram groups so far. The product works, the pricing works, the unit economics are positive. What I'm bad at is distribution.

What I'm working on next

- Dual-carrier failover got refined this month, the next big problem is discovery. Getting in front of the people who would actually use this (expats, remote workers, frequent international callers) without burning a marketing budget I don't have.

- Trustpilot and G2 review collection (post-call feedback popup is live and pinging Telegram on every 3-call streak, but the review pipeline is still manual).

- More virtual number countries — top requests so far are Brazil, India, Turkey, UAE.

What I'd love from this community

If you've launched a B2C product where you're trying to displace an entrenched but customer-hostile incumbent (international calling cards, expensive SaaS subscriptions, traditional banks, etc.) — what was the single thing that moved the needle on early adoption?

I'll be posting milestone updates here as things ship. Happy to dig into the carrier infrastructure, the SIP-wholesale economics, or the CDR reconciliation problem in the comments — whatever's interesting to you.

— Ivan

twin-phone.com