KUBRA Senior Developer interview questions

The process was straightforward: recruiter screen, technical assessment, HM/director interview, offer stage. Unfortunately, this is the worst interview and offer experience I've ever had. I received an offer that was considerably lower than expectations, and a full 10k lower than they had offered a former colleague of mine a month prior. At our previous company my colleague was a level below me, and I thought it reasonable to ask for a similar compensation rate. Other than that difference my former colleague was male, and I am female. I live in a higher COL area. Though I did not mention my knowledge of my former colleague's offer in my offer negotiation I thought that asking for 10k more in tech was incredibly reasonable. Offer negotiation is a part of the process. Worst thing they can do is say no, right? Wrong! They came back and rather than countering or simply saying "no the offer is firm" they simply rescinded the offer. Unheard of and incredibly unethical. I do not doubt my gender came into play here, and now it is my mission to tell anyone who will listen to not consider interviewing for this company.