My interview with the hiring manager was great. Fairly standard. The "coding challenge" was a bizarre collaborative exercise where I was handed an approximately three sentence "product spec" and some broken code, and then asked to fix it. My two interviewers each had probably 10 years less professional experience than me, and were unable to answer simple questions about how our "product" would be used which would have informed a number of technical trade-offs. They asked no probing questions, and offered hardly any feedback at all as I discussed various options. Eventually I was told that I didn't pass the code challenge, though no detail was given. Everybody was certainly friendly enough, and I thought the phone screen and hiring manager interviews were reasonable enough. But whatever rubric they have for the coding challenge seems to be fairly asinine, as I somehow "failed" what amounts to "make an API call and perform a database insert" after 15 years as an engineer.

I submitted my CV and after a week I had an initial call with the recruiter regarding my experience followed by a call with the hiring manager another week later. The hiring manager didn't asked any technical question, only about my experience and why I wanted to work at Klaviyo. He mentioned there will be 5-6 further rounds of interviews so expect a lengthy process. The conversation went fairly well but after a week I received an email saying they selected others for the next steps.