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Is it possible to verify an eBay UserID or Feedback score by using a given email address?
In order to verify an eBay UserID or the Feedback score for a given eBay UserID, the user must go through the Auth & Auth flow to generate a token for the application looking to make the verification.
The use case here is where a company creates an account in their system by asking for an email address as registration information with that company. The company would also like to ask for their eBay UserID so that they can get the public feedback score.
The issue is then how to verify that the eBay UserID provided is actually owned by that person.
Since an email address is used for user registration for that company, one might think that a validation method might be to use an API call such as GetUser and provide the email address as input to get back the eBay UserID associated with that email address.
However, this is not possible since the email address cannot be used in place of UserID in the GetUser call.
In order to verify the owner of an eBay user account, the company must send the user through the eBay Auth & Auth flow to generate an AuthToken for their application.
The auth token can then be used to make the GetUser API call.