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

SuperTokens.com

Can i make sso for 2 domains a.com & b.org with supertokens ?

For this it requires that supertokens is an OAuth provider. Which we are yet not

We are working on it, but until then, you can still use us for login as long as you can add the OAuth stuff on top yourself. There may be some library to help with that.

On the other hand, we do support SSO across sub domains. We do that by sharing the session via cookies.