Cozero (Germany) interview questions

Interviewed for a Senior Software Engineer role at Cozero. Overall, a frustrating and poorly structured process. The interview loop was long: recruiter call, Head of Engineering, then three back-to-back interviews on the same day lasting over three hours. A final stage with the co-founder was already scheduled and then cancelled after the previous round. The first two technical interviews were actually good. The code review and system design were relevant, well scoped, and clearly aligned with the role. No issues there. The Product & Data interview is where the process completely breaks down. There was no clear structure, no consistent line of questioning, and no obvious evaluation criteria. It felt unfocused and disorganised. After already passing two strong technical rounds, this stage came across as unnecessary and poorly designed. It was not clear what was being assessed or how a backend engineer was being evaluated in that setting. The rejection was generic and provided no meaningful feedback. However, since the process is sequential and you only move forward if you pass each stage, it’s clear the decision came from that Product & Data round. The biggest issue is the mismatch between the strong technical stages and a final decision being made based on an interview that doesn’t seem well defined or consistently run. In the end, this meant spending over 3 hours in interviews in a single stretch, essentially half a working day, only to be rejected based on a stage that lacked clarity and direction. That level of time investment simply isn’t justified by how the process is structured. Overall, the process feels inconsistent and overcomplicated for a company for a company that’s only been around for about 6 years and still relatively small. Would not recommend unless you’re willing to invest significant time into a process that may not be well aligned or fairly assessed end to end.