I applied through a recruiter.

I applied online for the Software Engineer role. The first stage was a recruiter screen, a fairly conversational call covering my background, why I was interested in Optiver, and what draws me to low-latency/trading systems work. After that I moved straight into a technical interview where I worked through a coding question with an engineer. The interviewer was friendly and cared about how I reasoned through the problem, not just the final answer. Talking through trade-offs out loud and handling edge cases helped. The process moved quickly, and I heard back about a week later.

Result: rejection