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open62541 is an open source C (C99) implementation of OPC UA licensed under the Mozilla Public License v2.0.


  • Based solely on IEC 62541
  • Open source license (Mozilla Public License v2.0)
  • Royalty free, available on GitHub


  • Written in C99 with architecture-specific plugins (POSIX, ...)
  • Runs on Windows, Linux, QNX, Android and diverse embedded systems
  • Compiled server can be smaller than 100kb


  • Event-based architecture
  • Single or multi-threaded


  • Information model can be modified at runtime
  • Generation of data types and information models from XML specification files

Latest release:

open62541 is maintained by

Commercial support partners of open62541