http uses a request/response style of communication
Request–response For simplicity, this pattern is typically implemented in a purely synchronous fashion, as in web service calls over HTTP, which holds a connection open and waits until the response is delivered or the timeout period expires. However, requestâ€“response may also be implemented asynchronously, with a response being returned at some unknown later time. This is often referred to as "sync over async", or "sync/async", and is common in enterprise application integration (EAI) implementations where slow aggregations, time-intensive functions, or human workflow must be performed before a response can be constructed and delivered.