> For the complete documentation index, see [llms.txt](https://adidas.gitbook.io/api-guidelines/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://adidas.gitbook.io/api-guidelines/rest-api-guidelines/core-principles/design-maturity.md).

# Design Maturity

## API Design Maturity

> How to design an API

Every API design **MUST** be **resource-centric** ([Web API Design Maturity Model Level 2](http://amundsen.com/talks/2016-11-apistrat-wadm/2016-11-apistrat-wadm.pdf)). That is an API design **MUST** revolve around Web-styled *resources*, *relations* between the resources and the *actions* the resources may afford.

An API design **MAY** be **affordance-centric** ([Web API Design Maturity Model Level 3](http://amundsen.com/talks/2016-11-apistrat-wadm/2016-11-apistrat-wadm.pdf)).

## API Design Implementation Maturity

> How to implement the API design

Every API design implementation using the HTTP protocol **MUST** use the appropriate **HTTP Request Method** ([Richardson Maturity Model Level 2](https://martinfowler.com/articles/richardsonMaturityModel.html#level2)) to implement an action afforded by a resource.

An API design implementation **SHOULD** include **hypermedia controls** (HATEOAS) ([Richardson Maturity Model Level 3](https://martinfowler.com/articles/richardsonMaturityModel.html#level3)).