A free app for Android, by Odio Dialer.

Odio Dialer is a FREE app that lets you make low-cost international calls to any mobile phone or landline. Simply choose your destination, select a phone number, and you’re done! It’s that easy.

Odio Dialer has the lowest latency of all Android apps, so you can call friends and family faster than ever before. And Odio Dialer is extremely reliable. We’ve been working on this app for over two years, and we’re happy to say that we’ve never had a single crash or bug report.

The quality of your calls is also exceptional, even on older devices. And with Odio, you can call your friends over Wi-Fi, 3G, LTE, and more. You can send DTMF tones with your calls, and the app supports both VoIP and SIP.