Difference between server sent events and Websockets in HTML5

WebSockets

WebSockets is a complicated technology that permits real-time interactive bidirectional communication between the client browser and a server. This is accomplished by establishing a standard method for the server to transmit information to the client without first receiving an invitation from the client, then enabling messages to be transferred between both while the connection remains open. In this approach, the client and therefore the server may have a two-way progressing dialogue with no problems. It is a computer communication technology that permits us to possess full-duplex communication channels over one TCP connection.

WebSocket connections are able to send data to the browser and receive data from the browser. A chat app may be an exemplar of a basic application that would use WebSockets. It is highly supported by web-browsers like Google Chrome, Microsoft Edge, Opera, Firefox, Safari, etc.

Advantages:

• WebSockets has the ability to transmit both binary data and UTF-8.
• WebSockets are bidirectional (allowing communication between the client and therefore the server).
• WebSockets have the power to detect a dropped client connection.
• Browser support compatibility is more with WebSockets.
• WebSockets are versatile in nature because of their ability to handle complex projects.

Disadvantages:

• WebSockets are more complex and task-demanding to set up. Because it requires a ton of upfront work.
• Browsers that are older than 2011 do not support WebSocket connections.
• When connections are terminated WebSockets don’t automatically recover  – it should be done manually and is part of the reason why there are many client-side libraries in existence.

Server-Sent Events

Server-Sent Events (SSE) is a technology that enables a browser (client) to receive automatic updates like text-based event data from a server via an HTTP connection. It’s a specification that explains how servers initiate data transfer with clients after establishing a client connection. They use a JavaScript API called EventSource to send message updates or continuous updates to a client to improve cross-browser streaming. It was first implemented on Opera 9 web browser.

SSE is commonly used to send message updates or continuous data streams to a browser client. In summary, a server-sent event is when updates are pushed (rather than pulled, or requested) from a server to a browser.

Advantages:

• Browsers supported by SSEs are Mozilla, Chrome, and Safari.
• SSEs, come with automatic reconnection, event IDs, and the ability to send arbitrary events.
• Transported over simple HTTP instead of a custom protocol.
• SSEs are most appreciated in the cases like updating statuses, push notifications, newsletters and news feeds because they support mono-directional communication.
• Compared to WebSockets, SSE is faster and more suitable to set up.

Disadvantages:

• SSE is limited to UTF-8 and does not support bidirectional data communication.
• Browser support is low in SSE.
• SSE is subject to limitations with regards to the maximum number of open connections. This can be especially painful when opening various tabs as the limit is per browser and set to a very low number (6).

Difference Between WebSockets and Server-Sent Events:

WebSockets	Server-Sent Events
WebSockets has the ability to transmit both binary data and UTF-8.	SSE is limited to UTF-8 only.
WebSockets are bidirectional (allowing communication between the client and therefore the server).	SSE is mono-directional it does not support bidirectional.
WebSockets are more complex and task-demanding to set up. Because it requires a ton of upfront work.	Compared to WebSockets, SSE is faster and more suitable to set up.
When connections are terminated WebSockets don’t automatically recover  – it should be done manually and is part of the reason why there are many client-side libraries in existence.	SSEs, come with automatic reconnection, event IDs, and the ability to send arbitrary events.
Browser support compatibility is more with WebSockets than SSE but browsers that are older than 2011 do not support WebSocket connections.	SSEs are most appreciated in the cases like updating statuses, push notifications, newsletters and news feeds because they support mono-directional communication.