Nexus is a protocol for arbitrary duration RPC operations. These operations are modeled using a predefined set of synchronous RPCs.
A Nexus caller sends a request to a Nexus server. The request is handled by a Nexus handler. The handler responds either with a result, or with a reference to an asynchronous operation. The caller can cancel an asynchronous operation, check for its outcome, or fetch its current state. The caller can also specify a callback URL that the handler will use to asynchronously deliver the result of an operation when it is complete.
Nexus is currently in development. For more information, see docs.temporal.io/nexus.