Module node-opcua-client

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	—	✅