Matrixport interview questions

There are three rounds of interviews for the company for this role. The first two rounds are virtual and technical, and the last round is in person and behavioural. At the start, the HR had stated an expected salary figure for the role, which I also agreed upon. However, after completing the three interview rounds, the HR came back with an offer 20% lower than the figure previously agreed upon. To exacerbate the issue, the HR tried to make light of the issue by saying that the budget had changed and I should find myself fortunate to have gone through the interview process to meet the outstanding people in the company. I found this to be extremely insulting and unprofessional; the HR recruiter knows that I would not have proceeded with the interview given the huge gap in salary expectations, but she still pushed me through the interview loop to give a lowball offer. There were many other red flags throughout the interview process: 1. Candidates were required to submit up to 6 months of payslips for the previous job, and when I enquired as to why this is needed, the recruiter was unable to explain properly. Instead, she tried to handwave the question away by saying that it was standard company procedure and a necessary part of employee information. 2. The manager I spoke with in person at the company was extremely condescending, and kept referring to Gen-Z candidates as soft and weak. The manager also kept emphasising on how she built the platform from scratch, but did not credit the software engineers behind the platform at all.