The OPC UA YAML DSL specification isn't just a nicer syntax for writing information models. It's the foundation for a fundamental shift in how the OPC UA community builds, reviews, shares, and evolves models. When your information model is a human-readable text file with a formal specification behind it, every modern software engineering practice suddenly becomes available. Let's explore what that future looks like.

Last week we made the case that OPC UA desperately needs a standard, human-readable modeling language. Today, we're delivering on that promise. We are publicly releasing the OPC UA YAML DSL Specification — a formal, vendor-neutral document that defines a declarative YAML authoring format compiling to conformant NodeSet2 XML. The specification is available now at /specification/.

OPC UA information models are the backbone of modern industrial interoperability. They describe how machines, sensors, and production lines expose their data to the world. Yet in 2026, the way we author these models is stuck in the early 2000s — hand-editing verbose XML, locked inside proprietary GUI tools, with no path to version control, code review, or CI/CD. The OPC UA community deserves better.

Describing complex industrial information models in text format is a massive step forward, but writing YAML structures without help can still lead to simple syntax errors or reference typos.

To deliver the ultimate developer experience, we are thrilled to announce first-class IDE Language Server (LSP) Integration for the OPC UA Modeler! This turns your favorite editors (like VS Code, VSCodium, or Monaco) into powerful, fully-loaded OPC UA development environments with instant autocompletion, real-time diagnostics, and inline hover documentation.

In industrial automation and complex information modeling, setting default values for deeply nested instance properties has historically been a tedious chore. Often, it required writing custom server-side bootstrapping code in C#, C++, or TypeScript to run after the server starts up.

With the latest release of OPC UA Modeler, we are excited to announce a massive upgrade to this workflow: Declarative Initializers combined with the brand-new, ultra-intuitive propertyValues: shorthand! Together with first-class IDE LSP Extension support, you can now configure complex default states inside your YAML model with instant autocomplete and zero boilerplate.

When modeling industrial systems with OPC UA, the debate between composition and inheritance often arises In object modeling, composition frequently proves to be a more flexible and powerful alternative to derivation (inheritance). While inheritance can result in complex and rigid hierarchies, composition facilitates the creation of flexible and reusable components.

Finite State machines can be easily defined with the Sterfive opcua modeler.

Creating OPCUA models is a difficult task that requires a good understanding of the OPCUA modeling paradigms and good knowledge of conventions and best practices. Extending or creating a new ObjectType or DataType has always been tedious and time-consuming. Name each node right, and organize the nodes within the context of an existing companion specification is always challenging. Most of the time, this modeling exercise requires deep expertise in this field.