Apply online, then HackerRank. I didn't make it past HackerRank because I didn't give myself enough time to finish, but they were doable questions, as long as you allocate enough time to finish them.
(HackerRank questions)
The following metrics were computed from 39 interview experiences for the Optiver Software Engineer (Internship) role in United States.
Optiver's interview process for their Software Engineer (Internship) roles in the United States is extremely selective, failing the vast majority of engineers.
Candidates reported having good feelings for Optiver's Software Engineer (Internship) interview process in United States.