OPC UA .NET Standard Stack
🆕 This is version 2.0 of the OPC UA .NET Standard Stack (current master).
Looking for the supported 1.x release? It lives on the
master378
branch (last release: 1.5.378). All new feature work happens here on
master; master378 continues to receive security and critical-bug
fixes for the 1.x line.
The official OPC Foundation reference implementation of OPC UA for
.NET — a cross-platform stack with client, server, PubSub,
GDS, complex types, and source-generated tooling. Used in production
across industrial control, manufacturing, energy, and IoT systems.
📦 What it is
- A full-stack OPC UA implementation — Core / Client / Server /
PubSub / GDS / LDS / Complex Types / Device Integration / Positioning libraries
built on .NET, with UA-TCP and HTTPS transports.
- Cross-platform — runs on .NET 10, .NET 9, .NET 8 (LTS),
.NET Framework 4.8; ships
Native-AOT-friendly assemblies.
- Conformance regression testing — the reference server is tested with the
Compliance Test Tool (CTT)
through the CTT regression workflow.
These results identify regressions; they do not constitute product
certification.
- Companion-spec coverage — Part 9 (Alarms & Conditions),
Part 10 (Programs), Part 11
(Historical Access), Part 13 (Aggregates), Part 16 (State Machines),
Part 17 (Alias Names), Part 18 (Role Management), Part 20 (File
Transfer), Part 100 (Device Integration), Part 110 (Asset Management
Basics), Parts 210/211 (Relative
Spatial Location and Global Positioning), OPC-10030 (ISA-95 Common
Model) with OPC-10031-4 Job Control V1/V2, OPC 30270 / OPC UA for Asset
Administration Shell V2 and V3, OPC 10100-1
(WoT Connectivity), Part 200 (Industrial Automation), OPC 40001-1/-2/-3/-4/-101
(Machinery with Process Values, Job Management, Energy and Result
Transfer), OPC 34100 (Energy Consumption Management), OPC 30081
(PA-DIM), OPC 40010-1 (Robotics), OPC 40100-1/-2
(Machine Vision control and asset management),
OPC 40501-1 and OPC 40505
(Machine Tools and independent wireless peripherals),
OPC 40210 (Geometric Measurement Systems, with its documented
upstream Production-facet exception), OPC 40020-1
(Cranes and Hoists),
OPC 40223 (Pumps and Vacuum Pumps),
OPC 30010 (AutoID Devices),
OPC 40200 (Weighing Technology) with OPC 30050 (PackML).
For the full feature breakdown see
OPC UA Profiles and Facets and the
What's New in 2.0 tour.
🚀 Getting started
To run a first OPC UA client and server, from NuGet packages or from the
samples in this repository, follow Getting started.
The documentation index then leads from the core concepts
to advanced and experimental features.
The recycling operator console demonstrates
live browser monitoring, native companion-specification inspection, material genealogy,
and authorized controls over the synthetic recycling line.
You need a stable .NET SDK
version 10.0.400 or later to build the repo. global.json selects the
highest installed stable SDK, including newer major versions. From the repository root:
dotnet restore UA.slnx
dotnet build UA.slnx
For the supported target frameworks and platform notes see
the Developer Guide. The official NuGet packages
are published to nuget.org under the OPCFoundation.NetStandard
prefix — the meta package
OPCFoundation.NetStandard.Opc.Ua
bundles a default set of stack packages; see its
package inventory.
Reference PubSub and other optional feature packages separately, or select
individual packages directly, e.g.
OPCFoundation.NetStandard.Opc.Ua.Client for clients or
OPCFoundation.NetStandard.Opc.Ua.Server for servers. Preview builds from
every successful master build are available from the
GitHub Packages NuGet feed,
which is the only feed they are published to. nuget.org receives a version
only through a manually approved promotion from a release/<major>.<minor>
branch — that is where the 2.0.0-preview.N packages already on nuget.org
came from, via the earlier release/2.0.0 line. To use those, enable
prerelease packages and float with 2.0.0-preview.* until 2.0.0 is
released. The XRegistry, WoT Connectivity, Robotics, CranesHoists,
Redundancy, Positioning, OpenUSD, and AI package families, the Vision.OpenUsd
renderer, and the Robotics MCP extension remain
preview packages when the root version is promoted to a stable version, and
keep their own -preview.N versions on nuget.org. This includes all CranesHoists
model/server/client/MCP packages and their Debug variants.
The Vision, MachineVision, MachineTool (including WMTP), and GMS
model/client/server packages and their MCP packages follow the root version
without a preview-only override;
development builds still inherit the root prerelease version. See
docs/ReleaseProcess.md for how and when stable
versions are released.
Samples
The platform-independent sample applications show how to use
the stack's core services and companion models in client/server workflows.
More applications, including platform-specific examples, are available in
the companion
OPC UA .NET Samples repository.
Developer tools
- UaLens — NativeAOT-capable desktop engineering workspace for secure connections,
monitoring, alarms, structured values, history, administration, PubSub, continuity diagnostics, and guided
companion-model tasks. See build and artifact qualification.
- OPC UA MCP Server — installable .NET tool and container
exposing OPC UA client operations to LLMs and Copilot. Embeddable libraries
provide Part 4 services, PubSub, diagnostics, Robotics and Vision, plus
industrial companion profiles for AMB, Machinery,
Scales, Pumps, AutoID, Device Integration, ISA-95 and Positioning. The
WoT and xRegistry profiles add
asset/registry management and bounded document validation, planning and
NodeSet conversion. Stack workflow profiles
provide GDS/credential issuance, roles/users, files, alarms, history, schemas,
and host-authorized PubSub and live WoT execution.
🔧 Migrating from 1.5.378 to 2.0
The 2.0 release introduces breaking API changes, and comes with a full
prescriptive migration guide that links to
per-area documentation for the migration
sub-topics.
Most of the mechanical migration work is automated:
OPCFoundation.NetStandard.Opc.Ua.MigrationAnalyzer NuGet —
install it in your project to get 26 analyzer rules through UA0030
(excluding UA0013, UA0016, UA0017, and the shim-only UA0029) plus
one-click code fixes for the patterns in the guide. Setup steps
are in the package's
NugetREADME.md.- Migration agent skill — the
opcua-v20-migration
skill walks Copilot / Claude / any coding agent through installing
the NuGet, running dotnet format analyzers to apply auto-fixes,
and handling the remaining manual changes. It selects the migration
sub-document for each symptom.
Copilot CLI discovers the skill automatically inside a clone. To install it
for use in any repository:
copilot plugin marketplace add OPCFoundation/UA-.NETStandard
copilot plugin install opcua-v20-migration@opcua-dotnet
If you are still on 1.x and not ready to upgrade, stay on the
master378
branch — it continues to receive security and critical-bug fixes.
🤝 Contributing and license
Community contributions are welcome. Fork the repository, make your
changes on a branch, and open a pull request; see
CONTRIBUTING.md for the contribution workflow.
Contributors must sign the OPC Foundation
Contributor License Agreement (CLA).
The CLA "I AGREE" gate is presented automatically on your first PR.
The project is licensed under the
OPC Foundation MIT License. Report security
vulnerabilities via the process documented in
SECURITY.md.
📚 Further reading
