What protocols are used for real-time data transmission on the server?

The following protocols are often used for real-time data transmission on servers:

• WebSocket: A bidirectional protocol based on TCP, providing full-duplex communication between client and server over a single connection. Ideal for interactive applications (chats, games, online editing).
• Server-Sent Events (SSE): Allows the server to send data to the client over a single HTTP connection in a one-way manner. Simpler than WebSocket, suitable for notifications, update feeds.
• MQTT (Message Queuing Telemetry Transport): A lightweight message exchange protocol based on a "subscribe/publish" model. Often used in IoT and mobile applications due to low resource consumption.

From lower-level or specialized protocols:

• UDP: An unreliable but fast protocol without connection establishment. Used in tasks where speed is crucial and data loss is acceptable (online games, audio/video streaming).
• WebRTC (Web Real-Time Communication): A set of protocols and APIs for direct media data transfer (audio, video) between clients (P2P) via browsers. Can be used on the server side for signaling and relaying.