The sasl-oauth branch in GitHub that has been open for a long while has now been merged into the master branch, and will be included in the next versioned release, 10.6.3.7.
Note that at this time, Indy still does not have any logic implemented to actually retrieve an access token from OAuth providers, as the requirements for doing that depend on each provider. But, once you have a token, you can use it in the new TIdSASLOAuth10A , TIdSASLOAuth2Bearer, and TIdSASLXOAuth2 components. Simply assign the token to the SASL’s Password property, or return it from the SASL’s OnGetAccessToken event.