WhatsApp: Free Between Users, Can't Call Phones
WhatsApp's biggest limitation is also its most misunderstood: it cannot call regular phone numbers. WhatsApp only handles app-to-app communication. If the person you're calling doesn't have WhatsApp, you simply can't reach them.
For calling other WhatsApp users, it's excellent — free voice and video calls with end-to-end encryption. But that's a different product category entirely.
Viber Out: The Hidden Calling Feature
Viber has a paid feature called Viber Out that lets you call real phone numbers. It's not prominently advertised, and many Viber users don't even know it exists.
Rates vary dramatically: $0.01/min to the US but $0.20+/min to some African countries. The pricing transparency isn't great — you need to check each destination individually. Calls are billed per minute (rounded up), so a 61-second call costs you for 2 minutes.
TwinPhone: Purpose-Built for Real Phone Calls
Unlike WhatsApp and Viber, TwinPhone was designed from day one for one purpose: calling real phone numbers internationally at the lowest possible cost.
Rates from $0.02/min, billed per minute — and the exact per-minute rate is shown before every call connects, with no connection fees and no hidden charges. Works in any browser — no app to install. Every call encrypted with TLS + SRTP. Adaptive audio handles poor connections gracefully.
It won't replace your messaging app, and it's not trying to. It replaces the expensive part of your phone bill.
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