Zest AI Data Scientist Interview Experience — Eight Rounds, Then Ghosted by a Vanishing HR

Let me share the funniest interview experience I've had recently.

I saw the posting online and applied on a whim. The recruiter emailed me to reach out. From start to finish there were 8 rounds total. Yes, 8, for a company this small.

First was the hiring manager round: resume and machine learning concepts.

Then a technical screen. The first question showed a graph where training, testing, and validation error all kept going down — what's causing this (overfitting), and how do you fix it. The second question was to write a simple Python function, something like creating new features based on some naming convention. Not too hard, basically just needed a dictionary.

Both of these rounds gave me a decision the same day.

Then came the virtual onsite — 6 rounds (haha, yes, 6 more).

Presentation: they give you a dataset of loan applicant data with a loan good/bad label, and you build a classification model. You prepare about a 30-minute presentation, and around 6 people show up to listen.

Technical: a data scientist asks about the data analysis, mostly around different ML model concepts, plus some domain knowledge about loans like fairness (it's fine if you don't know this stuff, just go with your intuition).

Coding (Python LeetCode): this one is with an engineer, two questions. First one is tree maximum depth. Second is find the minimum number of meeting rooms given a meeting schedule. I don't know the exact LeetCode numbers but they're definitely classic problems.

Technical again, another data scientist, mostly asking about the ML project on my resume.

Business case: a business analyst, asking mostly probability and simple math questions. Honestly, first time I've run into this kind of question in an interview. Felt pretty strange to me, not sure what the point of this round even was.

Last was a 30-minute wrap-up with the hiring manager. This was the weirdest round. I figured the HM would want to ask about my background or something, but instead he opened by having me go through every single interview I'd just had and asking what new things I'd learned from each one. Then at the end he asked a few more ML questions. And then he spent another ten-plus minutes explaining what his team actually does.

Overall, the interviewers I ran into were all pretty nice, and I could tell the company's work-life balance is decent, at least way better than those two DD interviewers I've run into before, lol. So even though the pay is genuinely very, very low and there's no stock or options, they still clearly put real effort into preparing for these interviews.

Then after a week with no news, I sent the recruiter a follow-up, and turns out the recruiter had already left the company. Absolutely ridiculous. This might be the most unprofessional recruiter I've ever dealt with.

I searched online afterward and it looks like a lot of people have gotten ghosted by them too. So, moving on.