Communication protocol providing full-duplex communication over a single TCP connection. Like having a phone conversation where both parties can talk simultaneously.
Chat applications use WebSocket to enable real-time messaging where messages appear instantly without refreshing.
WebSocket is an open protocol (RFC 6455), not a single cloud service. AWS API Gateway WebSocket APIs and Azure Web PubSub are managed services that handle connection state, scaling, and messaging patterns. On GCP and OCI, WebSockets are commonly implemented by running your own WebSocket-capable app (e.g., on Cloud Run/Compute Engine/OKE) behind a load balancer that supports WebSocket upgrades and long-lived connections.