Open Source OPC UA SDK – open62541

Open Source OPC UA SDK – open62541 can be downloaded for free from GitHub, under friendly permissible license terms. Unlike most other proprietary stack alternatives, open62541 does not have an SDK or runtime license fee. A question that might immediately pop-up in your mind would be that of our business model. Some of our open source users need additional support in learning the technology, putting in place their architectural design, software development, validation, and certification. They also expect annual maintenance contracts to manage updates and get speedy troubleshooting support and free of cost bug fixes. Our business model is to provide these additional services at competitive costs.


Additional Components for resource constraint embedded and TSN targets

The open62541 stack in GitHub is quite complete for use in resource-constrained embedded devices and time-sensitive-networking use cases.

At Kalycito we maintain additional components to achieve

  • Static allocation of memory
  • Reduce memory footprint
  • Certifiable and ready to use ports for bare metal environments and other operating systems like Realtime Linux, freeRTOS, VxWorks, etc
  • Time-sensitive-networking use-cases

Customers leverage these components to:

  • Speedup their feasibility study, prototyping and proof of concept projects
  • Achieve their Embedded footprint and performance targets
  • Certify their implementation with minimum surprises
    Software Stack Use Case PubSub Client/Server Security Processor &
    Nano Embedded Profile + PubSub Small sensors and actuators Small microcontrollers with external SRAM
    Micro embedded UA server profile + PubSub Gateway Devices, end nodes ARM Cortex M4
    Micro embedded device server profile + PubSub + Security PLCs, Controllers, Edge devices, end nodes ARM Cortex A9
    Micro embedded device server profile + PubSub + Security + TSN PLCs, Controllers, End-point-gateways, Edge devices, end nodes x86, ARM Cortex A9
    Embedded device server profile + PubSub + Security + TSN PLCs, Controllers , End-point-gateways, Edge devices, end nodes x86, ARM Cortex A9

    Certified by OPC Foundation

    open62541 is maintained by a community of developers and users. In Aug 2019, a sample server (server_ctt) built using open62541 v1.0 was certified by OPC Foundation to conformance with the “Micro Embedded Device Server” Profile of OPC Foundation. This includes support for OPC UA client/server communication, subscriptions and method calls. The following security policies – Basic128Rsa15, Basic256, and Basic256Sha256, and the facets method-server and node-management are supported as well.

    PubSub is not certified at this point (Aug-2020) due to the lack of official test cases and the testing tools.

    The certified release v1.0 was prepared by Fraunhofer IOSB and Kalycito Infotech with funding from an industry consortium via the Open Source Automation Development Lab (OSADL) eG


    For more information related to certifiability,


    Kalycito, OPC UA & Time Sensitive Networking

    Today, the biggest challenge companies face when exploring new business opportunities is interoperability and solving this challenge will unlock the potential of Industry 4.0. We are thought leaders in this space. The new initiative by the OPC Foundation – OPC UA FLC promises vendor independent and end-to-end connectivity from sensor to cloud. We build on top of this major global initiative.

    We are pioneers in building the open source eco-system for OPC UA including TSN. We started early and released PubSub in open source immediately after OPC Foundation released the part 14 specification. Even companies who hold proprietary IP in one part of what we do, leverage our work on other parts of the ecosystem to address their customer use cases. Our goal is to be a single eco-system for all the work involved in the Industry 4.0 end point device and edge device platforms, that includes optimizing the OS for real-time performance, time synchronization, functional and configuration parts of OPC UA, TSN and security. The following architecture diagram shows the different components that are part of an Industry 4.0 edge/end-point device.

    OPC UA Architecture

    Engaging with us is easy


    Join & fund community project

    • Get voting rights
    • Influence OSS roadmap
    • Reduced R&D costs

    Buy support & annual maintenance packages

    • Priority bug-fixes
    • On-demand support
    • Certifiable updates

    Avail consulting & integration services

    • Training & Consulting
    • Software Integration
    • Continuous Integration
opc ua open source

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opc ua technology adoption framework

Our industry 4.0 technology adoption framework

Kalycito Case study

Our industry 4.0 case study


OPC UA + TSN Quick Start Guide


This QSG explains how to run OPC UA stack open62541 with realtime PubSub on realtime Linux and TSN using Intel i210 Ethernet card.


Download our latest whitepaper


This whitepaper based on use-cases described in the ‘IEC/IEEE 60802 TSN Profile for Industrial Automation’ provides a series of measurements done in the Embedded Optimized OPC UA stack along with TSN drivers and a real-time Linux system and shows that the open source solution is able to achieve cutting edge performance demanded by modern Industry 4.0 devices.


Checkout our new online OPC UA courses

Code walk-through and OPC UA examples included

Click here