During the technical phone interview, I implemented an app that met all of the requirements completely and was able to finish writing four testcases that passed successfully. While I was working on the fifth testcase, the interviewer stopped me a few minutes early at the end of the interview and told me that I failed because I wasn't experienced enough with the testing library that I had chosen, due to the fact that I was taking too long to complete the last testcase.

Had a call with CTO, then a tech screen followed by an on-site. Didn't like the format with the onsite since the email pertaining to the structure is quite mis-leading. You will definitely be asked white-boarding questions. Each interviewer will asked you at least 2 questions. One algorithm and one main problem. The questions asked are geared towards product-related to fin-tech if that makes sense. This is much more a backend role than a full stack role based on all the questions asked on the interviews. The biggest issue is working with their data set and being required to solve their problems with little context. I feel that asking algorithm prior to the main problem is time-consuming.