WebSockets vs Server-Sent Events: Key differences and which to use in 2024

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WebSockets and Server-Sent Events are commonly used inRealtime applications where quick and efficient data transfer is a critical requirement.

WebSockets are more complex and demanding than SSE.
WebSockets offer a full-duplex TCP connection that is useful for a wide range of application scenarios.
SSE is a simpler solution, but it isn't extensible if your application requirements change.
Ably is a better option for complex applications that are likely to add new features over time.
With WebSocket, you can integrate with expert libraries and SDKs targeting every major language and development platform, with dedicated expert support available.
With SSE you can only send UTF-8 data over SSE (binary data is not supported).
For more documentation, see The WebSocket API on MDN.
The following code snippet creates a simple Node.js WebSocket server: After creating a stream with sseinit, a simple message is sent down the stream using sse.send() The following table provides a quick summary of the key differences between WebSocket and Server-Sent Events.
Which technology to use depends on your use case.
In this section, we will look at suitable use cases for both.
We’ll then show you how to connect to that server instance in the browser using the native Web socket API.
We will then look at experimenting with SSEs, implementing a simple server with express-sse.

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