asynchronously

Asynchronously refers to operations that are not performed at the same time or do not block execution while waiting for completion. The term contrasts with synchronous operation, in which tasks start and finish in a tightly coupled sequence. In computing, asynchronous describes patterns where a request is issued and the result is delivered later, often via callbacks, events, futures, or promises.

Asynchronous programming uses non-blocking I/O and event-driven designs to improve responsiveness and scalability. An event loop may coordinate many tasks and switch control when operations complete. Typical mechanisms include callbacks, futures, promises, and async/await syntax, which allow code to express asynchronous flow without resorting to multithreading.

Common environments include JavaScript with its event-driven model, Node.js, Python's asyncio, and languages like C# with the async/await keyword or Java's CompletableFuture. Asynchronous APIs are widely used for network requests, file I/O, and inter-process communication, where latency or waiting on external resources would otherwise stall the program.

In hardware and low-level systems, asynchronous can describe timing that does not rely on a global clock, or communication protocols that allow senders and receivers to operate independently. In networking, asynchronous communication enables decoupled producers and consumers through message queues or event-driven protocols.