WebSocket

WebSocket is a network protocol that provides persistent, bidirectional communication between a client and server over a single TCP connection. It begins with an HTTP handshake and then carries messages in either direction.

WebSocket handshake: An HTTP request-and-response exchange that negotiates an upgrade to the WebSocket protocol. It converts the initial HTTP connection into a WebSocket connection.
HTTP: An application protocol for exchanging requests and responses between clients and servers. WebSocket starts with HTTP but supports ongoing two-way communication beyond its request-response pattern.
Web chat: A system for exchanging messages between users through a web interface. WebSocket can deliver incoming messages and send replies over one live connection.
WebSocket scaling: The design of infrastructure that supports large numbers of concurrent WebSocket connections and messages. Long-lived connections consume server and network resources even when little data is moving.
WebSocket frame: A unit of WebSocket data containing control information and, when applicable, a payload. Frames carry messages and connection-control signals after the handshake.
Server-Sent Events: A browser technology for receiving a continuous stream of events from a server over HTTP. It provides server-to-client streaming where WebSocket supports communication in both directions.
Collaborative real-time editor: A shared editing system that propagates changes among participants as they occur. Persistent bidirectional updates support low-latency collaboration.
Load balancing: The distribution of incoming network traffic across multiple servers. WebSocket deployments must route connection upgrades and keep established connections attached to a server.
WebSocket subprotocol: An application-level protocol negotiated for use over a WebSocket connection. It lets endpoints agree on message conventions without changing WebSocket framing.
Long polling: A communication technique in which a client holds an HTTP request open until the server has data to return. It approximates server push through repeated HTTP requests rather than a persistent two-way protocol.

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