Advantages of WebSocket

1. WebSockets offer bi-directional communication in realtime.

2. WebSockets generally do not use 'XMLHttpRequest', and as such, headers are not sent every-time we need to get more information from the server. This, in turn, reduces the expensive data loads being sent to the server.

3. WebSocket connections can both send and receive data from the browser. A chat app is a good example of a basic application that could use WebSockets.

4. WebSockets can transmit both binary data and UTF-8

Advantages of Server Sent Event (SSE)

1. Transported over simple HTTP instead of a custom protocol

2. Can be poly-filled with javascript to"backport"SSE to browsers that do not support it yet.

3. Built-in support for re-connection and event-id

4. No trouble with corporate firewalls doing packet inspection

5. Useful for apps that enable one-way communication of data such as live stock prices

Similarity between Websockets and SSE

They function exactly the same way. They both push data from the server to client, a process also known as server push.

Differences between Websockets and SSE

• Unique Features

They are both equipped with unique features that make them specifically qualified for the kinds of tasks they handle. For instance, SSEs come with automatic reconnection, event IDs and the ability to send arbitrary events. WebSockets have the ability to detect a dropped client connection, unlike in SSEs where messages will have to be sent first before detecting the same issue.

• Browser Support

Another notable difference is the browser compatibility of the two technologies. In this regard, WebSockets have received more attention (and appreciation) than SSEs. More browsers support WebSockets natively than SSEs. However, there are available polyfills that simulate the SSE functionality to solve this issue.

• Transmission data types

WebSockets can transmit both binary data and UTF-8, whereas SSEs are limited to UTF-8.

• Connection Size

It´s good to know that SSEs suffer from a limitation to the maximum number of open connections, which can be especially painful when opening various tabs, as the limit is per browser is six.

• Extensibility

Compared to SSEs, WebSockets are a lot more complex and task-demanding to set up. This has its pitfalls, as it requires a lot of upfront work. Be that as it may, it also makes for a very stable and extensible application setting. SSE is a simpler and faster solution, but it isn’t extensible. If, for instance, your web application requirements were to change, it would need to be refactored using WebSockets, which are more versatile with the ability to handle complex projects.

• Use Cases

WebSockets provide bidirectional client-server communication between clients and servers. This kind of functionality is vastly applied and appreciated in technologies like real-time polling applications, chat applications, media players and the like. While SSEs do not provide bidirectional communication. However, there are so many applications where there’s no need to send data from the client. Cases like this are updating statuses, push notifications, newsletters and news feeds. In scenarios like this, SSEs are most appreciated.

References

1. WebSockets vs. Server-Sent Events (SSEs). (December 2021). Retrieved from https://www.scaledrone.com/blog/websockets-vs-server-sent-events-sses/.

2. WebSockets vs Server-Sent Events. (December 2021). Retrieved from https://ably.com/blog/websockets-vs-sse.

3. WebSockets vs Server-Sent Events. (December 2021). Retrieved from https://www.telerik.com/blogs/websockets-vs-server-sent-events.