> For the complete documentation index, see [llms.txt](https://sestra.gitbook.io/sestra-whitepaper/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://sestra.gitbook.io/sestra-whitepaper/integrations-and-lifecycle/request-and-session-lifecycle.md).

# Request & Session Lifecycle

## Request Lifecycle

* A request is sent to a protected API.
* The API checks whether access is allowed.
* If access is not allowed, a requirement is returned.
* The requester fulfills the requirement.
* Sestra validates the fulfillment.
* Access is granted for a limited time.
* The session expires automatically.

## Session Lifecycle

A session goes through these states:

* created
* pending
* fulfilled
* active
* expired

Sessions are temporary. They cannot be reused after expiration.