UA Cloud Library

What you actually use it for

• Finding out whether a model for your machine or device class already exists before you author one.
• Downloading a companion specification or vendor nodeset programmatically as part of a build, rather than clicking through a website.
• Publishing your own model so integrators and customers can pull it by namespace URI.
• Running a private, self-hosted instance as the internal registry for your organisation's nodesets, with the public library as upstream.
• Resolving a nodeset dependency chain when a model you were handed references namespaces you do not have.

Walkthrough

1. Search the public instance firstBrowse or search uacloudlibrary.opcfoundation.org for the namespace URI or model name. Search by URI where you can: names are ambiguous across vendors, URIs are not.
2. Read the Swagger documentation before scriptingThe service exposes a REST API with Swagger, so you can list, query and download models from a script or a build step. Read the current API surface rather than assuming endpoint shapes from an older example.
3. Download the nodeset and pin itPull the NodeSet2 file, commit it to your repository at a known revision, and compile against that copy. Fetching a model at build time from a remote service makes your build depend on someone else's publication schedule.
4. Check the model's dependenciesA model normally requires the namespaces it builds on, typically the base UA namespace and often DI and Machinery. Download the full dependency set and compile them together with UA-ModelCompiler or your stack's nodeset importer.
5. Self-host if the library must be reachable from an isolated networkThe service is containerised and PostgreSQL-backed, so an internal instance is a realistic option for an air-gapped or restricted plant network. Treat the API keys and the upload path as production security surface, not as a convenience.
6. Upload your own model with the metadata a consumer needsIf you publish, include the namespace URI, version and contact metadata, and keep old versions available. A consumer who cannot tell which version they downloaded cannot debug a mismatch later.

What it will not do

• Coverage is what has been published. A missing model means nobody uploaded it, not that no model exists.
• It stores and serves models; it does not validate that a model is a good one or that a product implements it.
• Upload, authentication and API-key handling are administrative surface you must manage on a self-hosted instance.
• Model versioning discipline is up to publishers, so two entries for the same namespace can differ in ways only a diff will reveal.
• It is not a substitute for the OPC Foundation's own nodeset repository when you need the canonical published companion specification files.

Alternatives

Last verified 7 September 2026 against OPC UA 1.05.07. OPC UA Connect is an educational resource and is not affiliated with the OPC Foundation.