SuperTokens is an open source authentication solution offering features like: Different types of login: Email / password, Passwordless (OTP or Magic link based).

SuperTokens.com

I see that I have to provide website url in the backend. Suppose I have two versions of my site running (like telegram ) on different domains. Then do I have to add both the domains in backend?

You should see this: https://supertokens.com/docs/thirdpartyemailpassword/common-customizations/sessions/share-sessions-across-sub-domains

Also, then the value of websitDomain should be the one that shows the login page to the user