Review Application Programming Interface

An application programming interface, or API, is a published contract between two pieces of software: one side may send a defined request, and the other agrees to answer in a defined way, giving access to specific capabilities or data.

An API describes how one program can ask another program to do something. It typically defines allowed operations, required inputs, returned outputs, identity, and error behavior.

Many AI products depend on vendor APIs. Their limits, permissions, pricing, data handling, reliability, and version changes become part of the larger system.

A company application sends a prompt and selected context to a model API, then receives a generated response for review.

An API is not the model itself. It is an access contract around a service, and the same model may be exposed through different APIs or products.

An API is the agreed doorway between software systems.

* [[input|Input]] * [[output|Output]] * [[handoff|Handoff]] * [[service-level-agreement|Service-Level Agreement]] * [[vendor-lock-in|Vendor Lock-In]]

* [OpenAPI Specification 3.0.4](https://spec.openapis.org/oas/v3.0.4.html) — authoritative industry specification describing a standard, language-agnostic interface through which people and software can understand and interact with an HTTP API.

* Treat an API as a system boundary and examine its [[handoff|Handoffs]] and [[service-level-agreement|Service-Level Agreement]].