Choosing a SIP server is a big decision if you’re building a VoIP solution. And in 2025, the two names that everyone’s still talking about are Kamailio and OpenSIPS. Both are powerful, open-source platforms — but which one is right for you?
In this post, we’ll break down the Kamailio vs OpenSIPS comparison in simple terms so you can make the right call for your business or project.
What Are Kamailio and OpenSIPS?
If you're new to this, both Kamailio and OpenSIPS are SIP servers. That means they handle call routing, registration, load balancing, NAT traversal, and other key VoIP tasks behind the scenes.
They were originally part of the same project (SER), but split years ago into two separate paths. Since then, both have evolved independently — and are now optimized for different needs.
Kamailio or OpenSIPS in 2025: What’s New?
Both servers are still under active development, and in 2025, they've stepped up their game. Here’s what makes them stand out this year:
Kamailio in 2025:
Highly scalable — can handle thousands of calls per second.
Used by big telcos and ISPs worldwide.
Great for complex, high-performance deployments.
Powerful scripting with flexibility for custom routing logic.
OpenSIPS in 2025:
Focused on modularity and ease of use.
Comes with a built-in Web GUI for easier management.
Supports media relaying and presence services.
Ideal for SMBs or mid-size VoIP providers who want faster deployment.
SIP Server Kamailio vs OpenSIPS: Side-by-Side
Here’s a quick comparison to help you decide which SIP server fits best:
|
Feature |
Kamailio |
OpenSIPS |
|---|---|---|
|
Performance |
Extremely high performance |
High, but slightly less |
|
Ease of Use |
Requires more scripting |
Easier with GUI |
|
Media Handling |
Requires external media server |
Supports media relaying |
|
GUI/Management Interface |
Command-line only |
Built-in GUI |
|
Scalability |
Excellent |
Very Good |
|
Preferred Use Case |
Large-scale, custom solutions |
Fast deployment, media support |
Which One Should You Choose in 2025?
It depends on your goals:
Choose Kamailio if you’re building a high-volume platform, need maximum flexibility, and have a skilled development team.
Go with OpenSIPS if you want a faster setup, need media relay capabilities, and prefer managing your server via a GUI.
Final Thoughts
The truth is, both Kamailio and OpenSIPS in 2025 are excellent choices. They’re reliable, fast, and trusted by VoIP developers around the world.
Your decision really comes down to the size of your project, your technical comfort level, and how much control you need over the SIP signaling.
So, what do you think — is Kamailio or OpenSIPS the right fit for your next VoIP project?
