node-opcua-client

Lightweight OPC UA client for Node.js — connect to any OPC UA server, browse, read, write, and subscribe to data changes.

Part of the node-opcua project — the most popular OPC UA stack for Node.js.

When to use this package

| Package | Use case | |---|---| | node-opcua-client | You only need client capabilities (smaller install, faster startup) | | node-opcua | You need both client and server in the same project |

Quick Start

npm install node-opcua-client

Requires Node.js 20 or later.

Connect, read, and disconnect

import {
  OPCUAClient,
  AttributeIds,
  DataValue,
} from "node-opcua-client";

(async () => {
  // 1. Create a client and connect to an OPC UA server
  const client = OPCUAClient.create({ endpointMustExist: false });
  await client.connect("opc.tcp://opcuademo.sterfive.com:26543");

  // 2. Create a session
  const session = await client.createSession();

  // 3. Read the server's current time (ns=0;i=2258)
  const dataValue: DataValue = await session.read({
    nodeId: "ns=0;i=2258",
    attributeId: AttributeIds.Value,
  });
  console.log("Server time:", dataValue.value.value);

  // 4. Clean up
  await session.close();
  await client.disconnect();
})();

📖 Documentation

• 📘 NodeOPCUA by Example — The best starting point: practical, ready-to-use examples with full explanations.
• 📚 API Reference — Complete API documentation.
• 🛠️ Client Tutorial — Step-by-step guide to building an OPC UA client in TypeScript.

🏢 Professional Support

| Feature | Community (GitHub) | Professional (Sterfive) | |---|:---:|:---:| | Bug reports via GitHub Issues | ✅ | ✅ | | CVE security advisories | After disclosure | Early access — patch before public disclosure | | Priority response time | — | ✅ | | Private support channel | — | ✅ | | Architecture & code review | — | ✅ | | Dedicated consulting hours | — | ✅ | | Certifiable version | — | ✅ |

📧 Contact: [email protected]

:heart: Sponsors

If you find this package valuable, please consider supporting the project:

• Become a sponsor on GitHub

Your sponsorship ensures long-term maintenance, new features, and continued OPC Foundation representation.

License

MIT — Copyright © 2014-2026 Etienne Rossignon / Sterfive SAS