> ## Documentation Index > Fetch the complete documentation index at: https://docs.activeviam.com/llms.txt > Use this file to discover all available pages before exploring further. # atoti.Authenticate Called with the URL of a request and return the HTTP headers necessary to authenticate it. There are some built-in implementations: * [`atoti.BasicAuthentication`](./atoti.authentication.BasicAuthentication#atoti.BasicAuthentication) * [`atoti.OAuth2ResourceOwnerPasswordAuthentication`](./atoti.authentication.OAuth2ResourceOwnerPasswordAuthentication#atoti.OAuth2ResourceOwnerPasswordAuthentication) * [`atoti.TokenAuthentication`](./atoti.authentication.TokenAuthentication#atoti.TokenAuthentication)