What does "Promise" mean in programming?

Promise is one of the most common terms in software development. This guide explains what it means, how it is used in practice, and why it matters, with real examples from the developer world.

Definition

An object representing the eventual result of an asynchronous operation. A Promise is in one of three states: pending (not yet resolved), fulfilled (completed successfully), or rejected (failed). Promises replaced nested callbacks and are the foundation of async/await syntax.

Example

"fetchUser(id) returns a Promise. If the request fails, the Promise rejects and the catch block runs."

Related terms

async / await
callback
event loop
concurrency
non-blocking

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