Authentication with external IDP

Dear Experts,
I have an api endpoint which returns jwt token without email, how can i do register if new user or logged in if user already registered.
Please help

rizwanmgm wrote:
What is an IDP ?
What is the link between the External IDP and a Registered Customer
What details are in the Token or what details can you find out from the Token ?
How can you find the Registered Customer from the IDP - Do you search by name or ?

If you answer these question then you know if you can
- search for an existing customer
- or Force the creation of a new Customer
and store the Token as a Custom Customer Attribute

You can check api document from api provider or ask them for support.

IDP third party identity provider, the token has claims like name, and identity number, dob etc.
how to authenticate new user to register by email or log in if user is already registered