Is there an e-commerce platform that uses Auth0? I am hoping to use Auth0 for account management and SSO and leverage an existing e-commerce platform.
I do not know any, but that does not mean it does not exist. Having said that it might be easier to search for platforms that allow you to integrate with a compliant OpenID Connect/OAuth 2.0 provider in terms of end-user authentication. Given the Auth0 service supports those protocols this could increase your range of options.