https://github.com/noonie2k/ex_aws_cognito_idp has some working code. I have added initiate_auth to this fork as a learning project. I would like to add more functionality, at least get_user, and global_sign_out but don’t want to duplicate efforts.
Are you the author of the linked project? I try to hand off ExAws projects to others these days since it became impossible to maintain all the different clients myself. I’m happy to merge someone’s project in and make them a collaborator if they want.