Is SOEM open source or proprietary software?

Thread Starter


Joined May 20, 2021
Hi everyone,
I am struggling to understand the licensing structure for SOEM(Simple Open EtherCAT Master), the open source implementation of EtherCAT.

Please refer to the following URL:

On Github, SOEM is distributed under the GPL v2 license. RT-LABS is named as the copyright holder of SOEM.
RT-LABS sells SOEM licenses for 3000 euros, what is the reason for this? Does this mean that by paying the price, I get a quality guarantee?

There are semiconductor manufacturers that sell a commercial version with a manufacturer's warranty, such as EEPROM writing software, with a clear statement that the evaluation version and the commercial version are exactly the same.



Joined Mar 31, 2012
I don't know about SOEM in particular, but it is often the case that companies will sell a license for something that can be obtained for "free" and what you are really buying are things like service and support as opposed to being all on your own with the free version.


Joined Jan 31, 2023
It seems that a commercial license from RT-LABS does not provide a quality guarantee, but purchasing a commercial license from RT-LABS can provide additional benefits such as technical support, access to proprietary extensions, and commercial liability.

Thread Starter


Joined May 20, 2021
I was able to get a rough idea of the atmosphere.

I remember reading somewhere that the view that selling open source for a fee is not a problem. Since any organization has consumed valuable human resources to create source code, I believe it is entitled to receive compensation for its efforts.

The source code for the library developed by Adafruit includes a statement asking users to buy the company's product if they like it. In fact, I usually buy a variety of breakout boards from Adafruit because all of their products are great.


Joined Jul 29, 2022
RT-LABS still retains the copyright to SOEM, and they give commercial licenses for 3000 euros.

Purchasing a commercial license from RT-LABS may give you additional benefits such as access to technical support and warranty. I think you should contact RT-LABS for more information on what exactly is included in the commercial license.