Before making any comparison/difference/similarity between SIP and WebRTC, we need to first understand what are these technologies and what they really do. In this post, we'll first briefly define SIP and WebRTC and then understand their motives, strengths, and weaknesses. Let's first start with the definition of SIP and then moving on to WebRTC.

SIP (Session Initiation Protocol) is a protocol for VoIP that is widely used for controlling multimedia communications such as voice and video calls over Internet Protocol (IP) networks. It delivers telephone services and unified communications to customers on IP-PBX and Unified Communications platforms.

WebRTC (Web Real-Time Communication), on the other hand, empowers traditional web browsers to perform browser-to-browser communication such as voice calling, video chat, and data sharing without the need of any plugin.

The definition of both communication technologies above brings an interesting point that both are used to offer collaboration and communication over an internet connection. So are they similar? yes, but not the same. This is one similarity that we discussed here. There are plenty of other similarities that many people starting to notice between WebRTC and SIP. This would lead to believe some people that both are competing technologies. But that's not the case actually.

SIP has grown in popularity over the last decade to the point where it's one of the biggest advances in communication and collaboration such as telephone calls, instant messaging, and video calling. A SIP user usually accesses these SIP services with a VoIP provider and soft-phone software that is installed on a PC or mobile device.

WebRTC also uses SIP under the hood for audio, video calling, text, and file sharing. But users access these services from a traditional web browser. That means the intermediary step of soft-phones is no longer required with the advent of WebRTC. Wow! That sounds great.

But the question arises, WebRTC and SIP dependent on each other, or is this dependent on the side? The is answer is no. There is no dependence between these two technologies. SIP can be used without using WebRTC, for example, using a softphone. Similarly, WebRTC can be used without relying on SIP. It can function with another protocol or without one altogether. However, from the user's perspective, WebRTC using SIP makes it easier to communicate from web browsers without using any additional software or plugin. The users don't have to learn any new software for audio, video, and data sharing.