CSipSimple is not available for iPhone but there are plenty of alternatives with similar functionality. The best iPhone alternative is Jami, which is both free and Open Source. If that doesn't suit you, our users have ranked more than 10 alternatives to CSipSimple and 11 are available for iPhone so hopefully you can find a suitable replacement. Other interesting iPhone alternatives to CSipSimple are Linphone, Zoiper, Talkatone and SessionTalk SIP Softphone.
Open source decentralized communication platform supporting secure end-to-end encrypted calls, messaging, group conferencing, file and media sharing, SIP compatibility, multi-device sync, and strong privacy, available across desktop and mobile systems.
Linphone is one of the most famous open source softphones in the world. It is fully SIP-based, for all calling, presence and IM features.
Zoiper IAX & SIP multilanguage and multiplatform (Windows, Linux and Mac OS X) softphone is a VoIP soft client, meant to work with any IP-based communications systems and infrastructure.
Talkatone gives you free calls, text messages, real-time location sharing and picture sharing to Facebook and Google friends, or any phone number in US.
With a superbly designed and intuitive user interface, the softphone offers easy set up with lots of preconfigured VoIP providers built in and smart call management features. Enjoy high quality enterprise communication features with zero effect on battery life.
The Callcentric Android app allows existing Callcentric customers to place calls worldwide using their Callcentric account.
Silent Phone – Secure Encrypted Video & Voice Mobile Phone Calls
You now have the ability to have secure encrypted phone calls between Silent Circle members, anywhere, anytime, with complete control.
Make a secure call as easy as an ordinary call and be sure of real safety.
Phoner provides business owner, sales people, lawyers, doctors, police officers and others with a second phone number to protect their identity and also gives the convenience of multiple phone numbers on one device.
Q-municate is a cross-platform app with a wide range of communication features including free messaging, file transfer, push notifications, audio/video calls.
KeeperChat - The leading secure messaging app.
• Private vault for messages, photos and videos • Private, encrypted media gallery (nothing is saved on device’s camera roll) • Biometric login and self-destruct protection for vault • Message retraction and self-destruct timer • Tw.
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Open Source SIP Voip client that is actively maintained.