// the find
Pro/opcua-animal-server
OPC UA Server for the OPC UA Companion Specification for Animals - A Tutorial
A tutorial OPC UA server in C that implements the 'Animal' companion specification — a deliberately toy domain used to teach how to build custom OPC UA information models with open62541. This is pedagogical code, not production infrastructure.
Uses open62541 as a submodule so the build is self-contained without hunting for a matching SDK version. CMake setup is minimal and actually works as described. Pairs with a companion spec repo and a written tutorial, so there is a learning path rather than just orphaned code. The toy domain (animals) keeps the signal-to-noise ratio high — you learn the OPC UA machinery without domain complexity getting in the way.
Abandoned in 2019 and open62541 has had significant API changes since then — the submodule is probably pinned to an old commit and you will hit breakage if you try to update. 15 stars and 7 forks after seven years means almost nobody uses it as a reference. The entire implementation is a single C file, which is fine for a tutorial but means there is nothing here to learn from structurally. No tests, no CI, no indication whether the companion spec itself is still maintained or has drifted.