WebSockets vs Server-Sent Events (SSE): Understanding Real-Time Communication Technologies

 WebSockets and Server-Sent Events (SSE) are both technologies used for real-time communication between a server and a client, but they have some key differences:

WebSockets

• Full Duplex Communication: WebSockets provide full-duplex communication, meaning data can be sent and received simultaneously between the client and server.
• Two-Way Communication: Both the client and server can initiate messages. This makes WebSockets suitable for applications where real-time updates are needed from both sides, such as chat applications, online gaming, or collaborative tools.
• Protocol: WebSockets establish a single long-lived connection over TCP. They start as an HTTP handshake, then switch to the WebSocket protocol.
• Binary and Text Data: WebSockets can send binary and text data, making them versatile for various applications.
• Use Cases: Ideal for real-time applications where both the client and server need to send messages independently, such as chat applications, live gaming, financial tickers, and collaborative editing tools.

Server-Sent Events (SSE)

• Unidirectional Communication: SSE allows the server to push updates to the client, but the client cannot send messages to the server over the same connection. The client can only receive messages.
• One-Way Communication: The communication is one-way from the server to the client. A separate HTTP request must be made if the client needs to send data to the server.
• Protocol: SSE uses HTTP and keeps the connection open for continuous updates. It's simpler as it doesn't require a protocol switch like WebSockets.
• Text Data Only: SSE can only send text data. If binary data is needed, it must be encoded as text (e.g., Base64).
• Automatic Reconnection: SSE includes built-in support for automatic reconnection if the connection is lost, which simplifies handling connection stability.
• Use Cases: Suitable for applications where the server needs to push updates to the client regularly, such as news feeds, live sports scores, or stock price updates.

Comparison Table

Feature	WebSockets	Server-Sent Events (SSE)
Communication Type	Full duplex (two-way)	Unidirectional (one-way)
Initiation of Messages	Both client and server	Server only
Protocol	Starts as HTTP, then switches to WebSocket	HTTP
Data Types	Binary and text	Text only
Complexity	More complex, requires protocol switch	Simpler, remains HTTP
Automatic Reconnection	Requires manual handling	Built-in
Use Cases	Chat apps, live gaming, financial tickers, collaborative tools	News feeds, live scores, stock price updates

Conclusion

• WebSockets are best suited for applications requiring bidirectional communication and real-time interactivity.
• SSE is more suitable for applications where the server needs to push continuous updates to the client with a simpler setup.