WebSocket is a two-way communication protocol that utilizes a single TCP connection to send/receive data.
Technically, WebSocket provides full-duplex communication between the server and the client, which allows real-time data transfer. For starters, it is similar to HTTP but with more benefits and a different use case.
Just like you type in http:// or https:// in your browser address bar to connect to a webpage, WebSocket utilizes a different scheme, i.e ws: or wss:—however, you cannot use it on a browser’s address field.
If you are a user interacting with an app or service through a browser, you cannot tell the difference and do not need to.
But, it is helpful to know more about WebSocket if you are a developer. Here, I highlight some fundamentals for it, along with recommended WebSocket servers you can use.
WebSocket vs. HTTP
Before exploring WebSocket, it is vital to learn its differences from HTTP.
| Bidirectional communication | Unidirectional communication |
| The server does not have to wait for a client request to send data once the connection is established. | The server must wait for the client to request data, meaning multiple connections must be made. |
| Useful for real-time web applications, chat applications, or games. | Anything that does not require two-way connections. |
| The connection ends only if the client or server closes it. | The connection closes after every request or response by the client/server. |
| Examples: Multiplayer games, Messaging apps, Stock market database | Examples: Google search, Social media, and Browser notifications. |
How Does a WebSocket Server Work?
A WebSocket server listens to a port of a TCP server.
The server is involved with making connections. To achieve that, here are the things it does:
- Interprets client requests.
- Sending back a response from the server to the client.
- Keep track of clients.
- Reading the masked data (encrypted) sent by the client and unmasking it.
You can review Mozilla’s official documentation to understand how to create/write WebSocket servers.
How Does a WebSocket Server Connection Work?
Now that you know the WebSocket protocol and its server, how does it all work?
To initiate a WebSocket connection, an HTTP connection is required.
HTTP starts the magic, even if it is not the hero in this story. Overall, all the technical jargon can be summed up in three steps:
- The client sends an HTTP connection to the server with appropriate headers that request an upgrade for the protocol.
- Once that goes in, the server responds that it is switching to a WebSocket protocol.
- Next, the client validates that the connection has been upgraded and gets ready to start transmitting data.
If you want to dive into how it works, the security model, client/server requirements, and more check out its Internet Standards Track document to learn more.
Why Are WebSockets Preferred for Real-time Connections?
WebSockets came into being because of the limitations of HTTP.
HTTP connections are unidirectional, i.e., you must wait for a request to complete before another start.
There is a workaround for this called long-polling, but it makes the HTTP request with a long time-out period. The server uses the long timeout to wait and push the data without a new HTTP request.
However, this ties up the server resources even when no data transfer occurs.
Real-time connections cannot afford the wait time. The data needs to flow continuously from the server to suffice the client’s requirements.
WebSockets provide a full-duplex connection that stays alive until the server/client drops the connection.
So, you get reliability and two-way communication that allows building real-time applications.
If you want the same perks for building your applications, here are some excellent WebSocker server options:
Soketi
Soketi is a simple, free, open-source solution that lets you focus on server architecture. It aims to be a fast WebSocket server compatible with Pusher while offering built-in app management.
It also provides a serverless WebSocket offering that can be deployed to Cloudflare workers. When writing this, it was in the open beta stage.
If you are looking to deploy a WebSocket server with maximum customization on your server, Soketi is a great pick.
Unfortunately, it does not offer any on-premise or managed solution.
Socket.io
Socket.IO is yet another open-source project that provides a low-overhead communication channel between the server and the client.
It supports falling back to HTTP long-polling if the connection is lost and will try to reconnect automatically.
Furthermore, it is compatible with Deno, a modern runtime for JavaScript and TypeScript built in Rust.
An incredibly popular WebSocket server that you can use for free on your server. You can follow the official documentation to learn more, as it does not offer an on-premise deployment service.
Pie Socket
If you are looking for a WebSocket solution for your enterprise or business and do not mind paying, Pie Socket is an excellent option.
Pie Socket is a premium offering, with companies like RedHat and Akamai using some services.
It also offers WebSocket API for mobile, desktop, and IoT devices. You can choose your preferred server region, get blockchain support, and prioritize customer support to help your business.
Pie Socket provides a 14-day trial (without a credit card) to let you test it out.
SocketCluster
Socket Cluster is an interesting toolkit that can also be deployed to Kubernetes.
It supports JWT authentication, lets you monitor and throttle data streams, and helps avoid memory leaks. SocketCluster also mentions that the message order will not be disrupted and can be deployed and scaled easily.
ws
ws is a Node.js WebSocket library that is simple to use and has a fast client/server implementation.
It is an incredibly popular WebSocket client and server for Node.js applications that support many features. Yet another free and open-source project that you can use as per your requirements.
Cowboy
Cowboy is a simple, fast HTTP server with WebSocket support, built with Erlang code.
Just because it uses Erlang, it is inherently valuable for building real-time applications requiring high availability. For instance, one can try using it for banking and e-commerce systems.
Sockette
Sockette is a lightweight wrapper around WebSocket that lets you automatically reconnect if the connection is lost.
Unfortunately, the project is no longer actively maintained. However, you can try it out for your use case.
Websocketd
Websocketd is a command-line tool that helps you wrap an existing command-line program and allow it to access via a WebSocket.
It should be helpful to build WebSocket-capable applications easily.
Similar to the previous project, it is no longer actively developed. However, you can try it out for your use cases. Explore its GitHub page to find out more.
NetCoreServer
As the name suggests, NetCoreServer is a .NET Core library (built with C#) supporting HTTP(S), WebSocket, and more connection protocols.
It also supports message protocol integration with Fast Binary Encoding, ensuring that the asynchronous socket server is ultra-fast and has low latency.
You can explore its GitHub page and documentation to learn more.
A Server for Handling WebSocket Connections is a Must
While you can pick any WebSocket servers and deploy them as per your requirements, most of them utilize a reverse proxy mechanism to minimize the load on the server and keep it as responsive as possible.
Millions of users interact with services that utilize the WebSocket protocol underneath. Starting with chat applications to multiplayer games, without a WebSocket server, we would have some severe issues communicating/getting information quickly.
That being said, you should only pick the best WebSocket server per your requirement. It is vital to try managing it yourself if you want total control and unlimited scalability at a fraction of the cost.
Choose the one that gives the maximum reliability your project deserves.