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Concept dictionary

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.

Review state
Reviewed in POC
Freshness
Current
Version
3

Also called

  • Application Programming Interface
  • API

Remember it this wayAn API is the agreed doorway between software systems.

In plain language

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.

Why it matters

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

Example

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

Common misconception

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.

Related terms

Sources

  • OpenAPI Specification 3.0.4authoritative industry specification describing a standard, language-agnostic interface through which people and software can understand and interact with an HTTP API.

Learn more

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

Reviewed in POC · last human review 2026-08-12 · content version 3 · visual version 1

Source and POC details

Source: learning-library/glossary/terms/application-programming-interface/term.md

Source hash: sha256:53f05f048977165b13ea55e5d316d7066c6ed196c4d5d57556a908c73effee7f

Media: POC-reviewed evidence; RS AI Learning Lab, Owned production asset.

Release: glossary-team-poc-0.5.5-2026-09-02 · not production approved