Custom login with SAML

We want to implement a custom login page using React and use Auth0 to login (using SAML) Salesfoce.

Auth0 is our Identity Provider and Salesforce the Service Provider. Now this connection is working but the users are redirect to the Auth0 default login.

Is there any way to implement this logic?

It will be like:

  1. User goes to
  2. Enters username and password in a custom form
  3. With these credentials, logins in the Auth0 user database
  4. Sends the SAML assertion to Salesforce (this is what we don’t know how to do it)