# OpenAPI

Concept · [Technical basics](https://ecosystem.samcarlton.com/technical)

Also called: OpenAPI spec, OpenAPI specification, Swagger, API spec

A standard format for describing what an [API](https://ecosystem.samcarlton.com/terms/api) offers: its addresses, what each one expects and what it returns. Tools can read the description to generate documentation, test code or AI tool definitions.

**For example:** A team publishes an OpenAPI file for its [REST API](https://ecosystem.samcarlton.com/rest-api), and partners generate working client code from it.

## Connects to (4)

- [REST API](https://ecosystem.samcarlton.com/rest-api): A common style of API where each kind of data lives at its own web address and software reads or changes it with standard web requests…
- [API contract](https://ecosystem.samcarlton.com/api-contract): An agreement on exactly what requests an API accepts and what responses it returns.
- [API](https://ecosystem.samcarlton.com/terms/api): Application programming interface.
- [Tool use](https://ecosystem.samcarlton.com/tool-use): A way for a model to ask the software around it to run a defined action, such as a search or a database lookup, and send back the result.

Map view: https://ecosystem.samcarlton.com/openapi