Choose an environment and client

Baseline: IOSignal JS 7.2.0. First verify local messaging with the quickstart.

Goal	Client or tool	Guide
HTML file	Browser IO, WebSocket	HTML and CDN
React, Svelte, Vite	Browser IO, WebSocket	Browser module
Node.js program	IO (WebSocket), IOCongSocket (TCP)	Node.js client
Arduino device	IOSignal C++, CongSocket (TCP)	Arduino installation
Terminal tests	iosignal-cli	CLI
Message relay server	Node.js Server or CLI	Create a server

Use import IO from 'iosignal/browser/esm/io.js' in a browser bundle and import { IO } from 'iosignal' in Node.js.

Server port is for WebSocket; congPort is for Arduino and IOCongSocket. Configure both when supporting both transports:

import { Server } from 'iosignal';
new Server({ port: 7777, congPort: 8888 });

IOSignal is the communication library. Remocon is a separate web application and Arduino example project built on it. See versions and scope.