// the find
node-opcua/node-opcua
Unlocking the Full Potential of OPC UA with Typescript and NodeJS - http://node-opcua.github.io/
node-opcua is a full OPC UA stack for Node.js written in TypeScript — both client and server sides. OPC UA is the industrial automation protocol for machine-to-machine communication (think PLCs, SCADA systems, factory floor equipment). If you need to talk to industrial hardware from JavaScript, this is your only serious option.
Full protocol coverage for the parts that matter in practice: secure channels, sessions, subscriptions, monitored items, alarms & conditions, complex types — all checked. The monorepo is split into ~60 focused packages so you can pull in only what you need (node-opcua-client vs the full stack). TypeScript throughout with generated types from the OPC UA spec, so the address space model is actually type-safe. Active maintenance with 10+ years of history and real industrial deployments backing it.
The features that matter for redundant/mission-critical deployments — redundancy, Node Management Service Set, QueryFirst/QueryNext, WebSocket transport — are all marked 'sponsors wanted' and effectively unimplemented. PubSub (the modern OPC UA transport replacing classic client-server) is commercial-only through Sterfive, not open source. The install command requires --unsafe-perms which is a red flag for any security-conscious environment. Best free documentation is a paid LeanPub book, and the free docs are thin — you'll spend real time in source code.