They are looking for free consultancy. Absolutely bizarre 7 stage interview process where tech skills / communication skills were tested. I enjoyed the chats but the final take home was a waste of 10 hours. Take home test was to code/configure their APIs (with poor instructions) and run and test the endpoints and then create a system design to integrate a payments system. My technical skills were already tested but they just wanted free consultancy on their systems. The hiring manager didn't see bothered about asking any questions to me regarding what I was talking about - he focused on the fact I spoke about the architecture rather than spend another 5 hours reading their documentation and making a diagram. Would definitely not recommend the process with the current structure.