Originally posted on dev.
With over 19k stars on GitHub and about 60 million weekly downloads on npm, ws is one of the most popular open-source libraries for real-time web application development
ws is a fast, easy-to-use, well-documented, and thoroughly-tested WebSocket client and server implementation that supports almost all browsers. As a result, ws is a favorite, go-to library for many developers, meaning its community is active and robust.
With over 8k stars on GitHub and almost 11 million weekly downloads on npm at the time of writing, SockJS is arguably one of the best JavaScrit libraries to build real-time web applications. SockJS follows the rules of the HTML5 WebSocket API and provides objects similar to WebSocket.
Pusher is a hosted service that makes it super-easy to add real-time data and functionality to web and mobile applications. It sits as a real-time layer between your servers and your clients. Pusher maintains persistent connections to the clients — over WebSocket if possible and falling back to HTTP-based connectivity — so that as soon as your servers have new data that they want to push to the clients they can do, instantly via Pusher.
5. Ably Realtime
Ably solves the most complex and demanding aspects of real-time engineering, making it easy for developers to power and scale real-time apps like chat, multiplayer games, real-time GPS location updates, IoT device control, and more. It also provides cloud infrastructure and APIs that help developers stream data between devices in real-time.
With over 40 Client Library SDKs and native support for more than six real-time protocols, getting started for any use case is fast and simple.
Deepstream is an open-source library for real-time web application development. The library, which is built with Node.js and Engine.io, helps developers build frontend web applications that perform real-time updates while requiring minimal backend code.
The Deepstream comes with a client library for the browser that lets the developer create and update data records on the fly. The client library relays updates to the server, which propagates the new data to other subscribed clients. The developer doesn’t have to write any specialized backend code to handle the changes or propagate the events.
In many modern web applications, WebSockets are used to implement realtime, live-updating user interfaces. When some data is updated on the server, a message is typically sent over a WebSocket connection to be handled by the client. This provides a more robust, efficient alternative to continually polling your application for changes.