IP Phone Apps

You'll find a nice selection of useable IP telephony apps for smartphones, Windows, Mac and a few for Linux - as long as they support SIP and are not locked to a specific provider. Some are free, some are based on a one-time payment and others on a small monthly subscription.

Mobile apps

We recommend apps with Push function, which reduces power consumption enormously and makes receiving calls more reliable. We have good experiences with these, but there are many more we have not tested.

• Acrobits Softphone and Groundwire with Push (one-time fee) - Redspot's recommendation.
• Bria Solo, formerly X-Lite (free basic edition for a very limited number of weekly calls - not recommended unless you pay the subscription).
• Zoiper Lite and Premium for iOS and Android (subscription).
• 3CX, with Push, only for 3CX PBX's (free).

Apps for Windows, Mac and Linux

We have good experiences with these, but there are many more we have not tested.

• Bria Solo, formerly X-Lite (basic edition is free for a very limited number of weekly calls - not recommended unless you pay the subscription). 
• Zoiper 5 also for Linux (basic version free for private use).