Best choice for an OPC UA Stack

Stefan Profanter
2 min readAug 28, 2023

You are looking for an OPC UA Stack? You want to start right away without paying? And you know C/C++?

tl;dr; Check out

Seems you got lucky or almost won the lottery! There are already some awesome people out in the world (including myself) which invest a lot of time to provide you some nice piece of open source software.

One of the most used and most starred open source OPC UA stacks ist the open62541 stack. It is gaining more and more visibility and is used by many different other open-source and commercial projects. Some of them are listed here.


open62541 is an open source implementation of OPC UA (OPC Unified Architecture) aka IEC 62541 licensed under Mozilla Public License v2.0. It implements most of the features specified in the OPC UA specification and new features are constantly being added.

A full list of supported features can be found in the file.

The core developers, where I’m also a proud member, not only focus on the implementation of new features, but also on:

  • testing the stack with the official compliance testing tools (CTT)
  • continuous integration builds for every commit
  • ensuring a high code quality using static code analysis
  • > 80% unit test coverage
  • support of different operating system architectures. Even microcontrollers are supported!
  • fuzz-testing using Google’s oss-fuzz

What about commercial support?

There are even some companies which provide commercial support for the open62541 open source stack. An up-to-date list can always be found in the official repository

Still not convinced?

Take a break, eat a “Leberkäse roll”! Feel the bavarian spirit and yell: OPC UA rocks!

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Stefan Profanter

I love to program and write code in various Programming Languages and am now focusing on Automating as much as Possible.