requestresponse

Request-response is a communication pattern used in computing in which a client sends a request to a server or service and awaits a reply. The interaction is typically synchronous, with the client blocked until the response is returned. The term is commonly written as request-response or request/response. In some systems, asynchronous variants use correlation identifiers, callbacks, or polling to deliver the reply when ready.

Common implementations include HTTP-based APIs (such as REST or gRPC) and remote procedure calls, as well as messaging systems that emulate request-response through temporary reply queues or reply topics. The request generally includes a method or action and a payload; the response carries a status code and a payload.

Key characteristics include a defined request and response format, a channel or endpoint, and a mechanism to match responses to requests (often a correlation identifier). Many environments enforce statelessness at the server side, enable timeouts and retries, and support error handling and idempotency considerations.

In practice, request-response underpins web services, APIs, and distributed systems. Benefits include predictability and straightforward testing; drawbacks include potential latency sensitivity and tight coupling between client and server. Patterns such as asynchronous request/response, streaming, or switching to message queues can mitigate scalability and resilience concerns, and are commonly used to complement direct request-response interactions.