> For AI agents: [llms.txt](https://docs.trustedauth.com/llms.txt) provides a Markdown index of this documentation.

# Administration API core concepts

Use this section to understand authentication, authorization, and the available Administration API categories.

## Topics in this section

[📄️Authentication and authorization Use this page to understand how Administration API authentication works before you call protected endpoints. For complete operation details, see the Administration API reference.](/api/admin-api/core-concepts/authentication-and-authorization.md)

[📄️Administration API categories Use this page to understand how Entrust Identity as a Service Administration API endpoints are grouped before you browse the generated reference. Each category name below links to the matching reference section.](/api/admin-api/core-concepts/api-categories.md)