Klaviyo Full Stack Engineer interview with API design and system improvement rounds

My first contact was a quick recruiter screen. After that, I received the CodeSignal link for the online assessment. Once I completed it, the process moved into a longer onsite structure covering past work, technical thinking, and collaboration. The onsite included several technical and behavioral interviews. In one round, I went deep into past work and system design decisions, explaining the arc…

Shared by a candidate · reported Apr 2026. Interview formats change; use it as a guide, not a script.