It started with a 30 minute call from the recruiter to go over my general background. My understanding is that normally there would have been a take-home exercise after this, but we skipped this in my case. Next was a 1 hour phone interview with the hiring manager to dive deeper into past experience, as well as a shared-screen CoderPad exercise. Finally, I was invited to an on-site consisting of three 1 hour interviews covering algorithms, data structures, and systems design. We also discussed my background during these sessions and how it could relate to the role at Sigma. There was ample time to discuss the interviewer's role at Sigma, what they were working on, and how product gets built. It was very clear everyone I talked to was passionate about the company and product, and I was particularly impressed with how seasoned the members of the leadership team I met were. The recruiter was very communicative throughout and checking in regularly to make sure I was comfortable with the way the interview was progressing. Overall, it was a very empathetic and extremely positive interview experience.