# API (application programming interface) · Glossary
A defined interface that lets one piece of software request data or actions from another, according to agreed rules about inputs, outputs and permissions.
[Glossary](/glossary) · Platform and software engineering

# API (application programming interface)

     A defined interface that lets one piece of software request data or actions from another, according to agreed rules about inputs, outputs and permissions. APIs are how modern applications, data platforms and AI tools connect.

## Why it matters

     APIs determine how easily systems can be integrated, replaced and automated. Well-designed APIs reduce manual rekeying and brittle point-to-point integrations; poorly secured ones are a common route for data exposure.

     AI agents and copilots act on the world largely through APIs, so API design, authentication, rate limits and logging are central to AI safety as well as integration.

## In practice

     For example, a UK housing association might expose an internal API for its repairs system so the tenant portal, contact centre and a triage assistant all create and update jobs through the same validated interface.

## Where Rodan fits

     Rodan designs and builds APIs as part of [Software and Product Engineering](https://rodan.io/software-product-engineering) and [Digital Products and Platforms](https://rodan.io/what-we-build/digital-products-platforms).

## Related terms

- [JSON](/glossary#json)

- [Tool calling](/glossary#tool-calling)

- [Model Context Protocol (MCP)](/glossary#model-context-protocol)

- [Event-driven architecture](/glossary/event-driven-architecture)

- [Zero trust](/glossary#zero-trust)

- [Agent2Agent (A2A) protocol](/glossary/agent2agent-protocol)

- [Embedded analytics](/glossary/embedded-analytics)

- [Legacy modernisation](/glossary/legacy-modernisation)

- [Model serving](/glossary/model-serving)

- [Reverse ETL](/glossary/reverse-etl)

- [Robotic process automation (RPA)](/glossary/robotic-process-automation)
HTML: https://rodan.io/glossary/api