Websites using Sockjs

Okay, let s break down SockJS:

What is SockJS?

SockJS is a browser JavaScript library that provides a fallback mechanism for establishing a persistent, bidirectional communication channel (like a WebSocket) between a web browser and a server. Its primary goal is to provide a WebSocket-like object even when native WebSockets are not available or blocked.

In essence, SockJS tries to use WebSocket first. If that fails (due to browser limitations, firewalls, proxies, etc.), it falls back to other protocols and transports like:

• HTTP Streaming: The server continuously sends data to the client over a single long-lived HTTP connection.
• HTTP Long Polling: The client makes an HTTP request, and the server holds the connection open until it has data to send. The client then immediately makes a new request.
• JSONP Polling: A fallback mechanism that uses the JSONP technique for cross-domain communication (less efficient and less secure).
• Iframe-based techniques: Used for some older browsers that have limited cross-domain capabilities.

Key Benefits:

• Cross-Browser Compatibility: Works across a wide range of browsers, including older ones that don t support WebSockets.
• Reliability: Handles network disruptions and attempts to re-establish connections.
• Transparent Fallback: Developers write code as if they are using WebSockets; SockJS handles the underlying transport negotiation.
• Server-Side Support: There are server-side implementations (libraries) available for various languages/frameworks (Node.js, Java, Python, Ruby, etc.).

Revenue and Company Details

• SockJS is Open Source: It s a free, open-source project, typically licensed under a permissive license like the MIT license. This means there is no central company that owns it and generates direct revenue from it.
• Maintenance & Support: SockJS is maintained by a community of contributors. There isn t a commercial entity selling SockJS licenses or support contracts.
• Indirect Revenue (Possible): Companies might use SockJS as part of a larger commercial product or service. In those cases, the revenue is derived from that broader offering, not directly from SockJS.

Alternatives to SockJS

If your priority is real-time communication but you want to consider alternatives, here are some common options:

• WebSocket API (Native): If you are only targeting modern browsers and network conditions are favorable, using native WebSockets directly is the most efficient option.

• Socket.IO: A very popular library that builds upon WebSocket and provides fallbacks similar to SockJS. It offers additional features like automatic reconnection, broadcasting, and namespacing. It handles the transport negotiation for you and provides a higher-level API. Socket.IO is a strong alternative to SockJS. Socket.IO is also open-source, but developed by a commercial entity (Automattic) that also provides hosted versions of Socket.IO.

• SignalR (Microsoft): A library for .NET developers for adding real-time web functionality to applications. It supports WebSocket and fallbacks to other transports.

• Ably: A commercial platform-as-a-service (PaaS) specifically designed for real-time messaging. It provides a robust and scalable infrastructure, guaranteed message delivery, and a variety of features. Ably is a good choice if you want a managed solution and are willing to pay for it.

• Pusher: Another commercial PaaS for real-time communication. It offers a similar set of features to Ably, including a scalable infrastructure, message persistence, and various client libraries.

• Firebase Realtime Database/Cloud Firestore: Databases that offer real-time data synchronization capabilities. While not strictly real-time communication libraries, they can be used to build real-time applications. These are part of Google s Firebase platform.

• MQTT (Message Queuing Telemetry Transport): A lightweight messaging protocol often used in IoT (Internet of Things) applications. It can be used for real-time communication in web applications as well.

• gRPC: A high-performance, open-source universal RPC (Remote Procedure Call) framework developed by Google. It can be used for building real-time applications, although it s generally more complex to set up than some of the other options.

Pricing (SockJS and Alternatives)

• SockJS: Free (open-source)
• Socket.IO: Free (open-source), but Automattic offers commercial services around it.
• SignalR: Free (if using the open-source version), but costs are associated with the Azure services if using the managed Azure SignalR Service.
• Ably/Pusher: Commercial. Typically offer tiered pricing based on usage (number of messages, connections, etc.). They usually have free tiers for development and very small applications.
• Firebase Realtime Database/Cloud Firestore: Offer a generous free tier, but costs increase as your usage grows (data storage, bandwidth, operations).

Customer Care/Support

• SockJS: Since it s open-source, support primarily comes from the community. You can find help on:
  • GitHub (issues, discussions)
  • Stack Overflow (using the sockjs tag)
  • Online forums and communities related to the server-side framework you re using (e.g., Node.js, Spring).
• Socket.IO: The Socket.IO website has documentation and tutorials. Automattic may offer commercial support depending on the services you use.
• SignalR: Microsoft provides documentation and support through its Azure portal and community forums.
• Ably/Pusher: These commercial platforms offer dedicated customer support channels, including documentation, email, and sometimes phone support.
• Firebase: Google provides documentation and support through its Firebase console and community forums.

How to Choose?

The best choice depends on your specific requirements:

• Simplicity and Legacy Browser Support: SockJS is a solid choice if you need to support older browsers and want a simple, transparent fallback mechanism.
• Features and Ease of Use: Socket.IO is a popular option for its ease of use, additional features, and active community.
• Scalability and Reliability (Managed): Ably and Pusher are excellent choices if you need a highly scalable and reliable real-time infrastructure and want a managed solution.
• .NET Development: SignalR is the natural choice if you re building .NET applications.
• Integration with Firebase: Firebase Realtime Database/Cloud Firestore is a good option if you re already using the Firebase platform.

In summary, SockJS is a valuable open-source library for providing WebSocket-like communication across a wide range of browsers. However, consider the alternatives based on your specific project needs and priorities. Remember to evaluate factors like browser compatibility, scalability requirements, ease of use, and whether you prefer a self-hosted or managed solution.