Mortgage Offer API


The Mortgage Offer API calculates an individual, indicative mortgage offer based on information entered about the borrower, his or her desired real estate object and financing structure. The resulting mortgage offer is non-binding.


What are the key features?

  • Simple – a few input parameters are sufficient, no need to fill in any forms
  • Real-time answer – immediate indicative mortgage offer, no need to wait
  • Indicative offer – allows realistic financial planning
  • Individual offer – takes object and borrower data into consideration

What output data can I get?

  • Interest cost per month
  • Interest rate

What input data is required?

  • Details of the object to be financed, such as type, location and market value
  • Details of the borrower and the loan, such as mortgage amount, household income and equity
  • Details of the desired financing structure, such as tranches, amounts, start date and duration

Some of the input parameters are optional; providing them will result in a more accurate indicative mortgage offer.

How can I use this API?

1. Evaluate Partnership

Get in touch with us, if you are interested in using this API as a key4 partner. The details are described in Getting started in the key4 ecosystem

2. Get API Credentials

Once you are a key4 partner, you will get your credentials for calling the API.

3. Call API

For details on how to call the API, please check the API reference