An Application Programming Interface: a defined set of operations, inputs, and outputs through which software components or services communicate without exposing their internal implementation, enabling modular composition and system integration.
In Plain Terms
- A standard socket that lets two pieces of software talk to each other: one program can ask another to do something or hand over data through an agreed set of requests, without needing to know how the other works inside.
Semantic Classification
Content
- An API specifies the contract by which one piece of software requests services from another, defining available operations, the structure of requests and responses, and expected behaviour. By hiding internal details behind a stable interface, it lets independently developed components interoperate and evolve.
- Web APIs are commonly exposed over HTTP using styles such as REST, with data encoded in formats like JSON. Well-designed APIs support versioning, authentication and clear error semantics, and are a foundation for integration between systems and services.