The Problem#
OPC-UA is the industry standard for machine-to-machine communication in industrial automation — but existing Node-RED OPC-UA nodes waste resources by opening a separate TCP connection per node, don’t support batch operations, and make certificate management painful. There’s a gap between what OPC-UA can do and what’s practical in a visual programming environment.
The Solution#
A modern OPC-UA suite for Node-RED that uses shared connections, batch operations, and drag-and-drop certificates — from simple tag reads to event subscriptions and embedded servers.
What is OPC-UA?#
OPC Unified Architecture is the interoperability standard for secure, reliable data exchange in industrial automation. It’s platform-independent, vendor-neutral, and supported by virtually every major PLC, SCADA, and MES vendor.
11 Nodes#
- opcua-endpoint — Shared connection pooling with reference counting (one TCP connection per endpoint, not per node)
- opcua-client — All-in-one node for read, write, subscribe, browse, methods, history, and discovery
- opcua-item — Visual batch operation builder through node chaining
- opcua-browser — Address space navigation with recursive traversal
- opcua-browse-client — Interactive address space browser with visual tree selection in the editor
- opcua-method — Method invocation with auto-detected typed arguments
- opcua-event — Event subscription for alarm conditions and custom event types
- opcua-server — Embedded OPC-UA server for testing and integration
- opcua-pubsub-connection — Shared OPC-UA PubSub transport configuration for UDP multicast or MQTT
- opcua-publisher — Publishes DataSets over PubSub connections in acyclic or cyclic modes
- opcua-subscriber — Receives and decodes DataSets over PubSub connections with filtering
Shared Connections#
Unlike legacy packages that open one TCP connection per node, this suite uses reference-counted connection pooling. Multiple nodes pointing to the same endpoint share a single TCP connection — automatically cleaned up when the last node closes.
Batch Operations#
Single OPC-UA service calls handle multiple variables simultaneously. Chain opcua-item nodes to visually build batch configurations:
Security#
- Drag-and-drop certificate upload in the editor
- Security modes: None, Sign, SignAndEncrypt
- Optional username/password authentication
Why OPC-UA?#
| Feature | Modbus | MQTT | OPC-UA |
|---|---|---|---|
| Data typing | No | No | Yes (rich types) |
| Information model | No | No | Yes (browsable) |
| Security | None | TLS | TLS + certificates + auth |
| Discovery | No | No | Yes (automatic) |
| Method calls | No | No | Yes |
| Historical data | No | No | Yes (built-in) |
| Industry adoption | Legacy | IT/IoT | OT/Automation |
Quality#
- 600+ tests across 30 spec files, including integration tests against an embedded test server
- Docker support for local development and CI
- Automatic datatype detection from JavaScript primitives
- MIT licensed



