> ## Documentation Index
> Fetch the complete documentation index at: https://developers.authlete.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Access Token Verification in Userinfo API

> Technical information on how Authlete's Userinfo API internally verifies access tokens eliminating the need for the authorization server to make a separate request to Authlete's introspection API.

Authlete's [/auth/userinfo/issue](/api-reference/userinfo-endpoint/issue-userinfo-response) API does internally verify access token in a request from authorization server.

Thus authorization server doesn't have to make a request to Authlete's introspection API ([/auth/introspection](/api-reference/introspection-endpoint/process-introspection-request)) in advance of using the Userinfo API.