The system can be simplified to a series of events:

An applicant navigates towards a Partner website which has an Application/Eligibility Check form that collects the applicant's data to be sent to us.
The form is completed by the user and the data is sent from the Partner website to our endpoint.
Our Partner API service will return a response that contains details about the best offer and a redirect URL to navigate the applicant towards.
1. This redirect URL can be towards the offers page, or it maybe towards our own application form to amend any data that had validation issues.
2. If the user has no offers, it may be that there is no redirect URL provided and therefore you may choose to keep the user in your own journey.