How to implement VoIP + SIP in iPhone? [closed]

Answer 1

If it's still relevant: use pjsip . It's a SIP library written in C. You must compile the source for iphone, it is described in the docs here. After that take a look at a very basic sample application here. It isn't very hard to use even if you don't know C, or how to compile libraries. Which was my case.

UPDATE Please be aware that pjsip uses GPL license.

Answer 2

Another option is Twilio Client which has an iOS SDK. With Twilio you don't have to maintain any of the telephony infrastructure.

(I worked at Twilio)

Answer 3

Rebtel is already the world’s second-largest mobile VoIP provider behind Skype. Rebtel Takes On Twilio, Launches Free VoIP SDK For iOS And Android App

Rebtel API

Answer 4

I think you should check my answer in this link.

iOS: Open Source VoIP/SIP Objective-C Code

Also check

SIP library for iOS with non-GPL license

You can also try OZeki,SIphone etc

Answer 5

There is a helper to handle calls in iOS Apple Standard library CallKit Apple Documentation - CallKit

There is one lecture about it here WWDC 2016

And, there is a tutorial in Ray Wenderlich here

You still might need some library to handle SIP connections and handle incoming calls.

Open source library linphone

Paid library voipsipsdk