HackerRank test for 90 mins: Multiple choice questions, questions for explaining code/concepts, and a question for coding up an algorithm.

The algorithm question was rather challenging; this might actually be the hardest part of the whole process, so be prepared to write good code.

If successful, a behavioral interview with HR. They also measure your knowledge of HFT, market making, etc.

Then, code pairing with 2 developers, where they ask you to write an algorithm (in my case, it was implementing a data structure with a few methods). It was not hard, but you need to communicate your ideas and edge cases clearly. They also care about concurrency and thread safety.

After that, on-site interviews in Amsterdam. This stage lasts about half a day:

• Interview with managers, which consists of a project deep dive, behavioral questions on a deeper level, explaining some technical concepts, and business knowledge. If they see that you're knowledgeable, they might test the limits of that knowledge, which is a positive indicator.

• Technical interview with developers: project deep dive on a deeper technical level, follow-up questions to test your technical knowledge based on what you listed in your CV, and a system design question (architecture, why you chose this, etc.).

• Lunch with a team member to ask questions and get a feel for the culture.

• Final interview with the recruiter and a tour around the office. This is more of a discussion rather than an interview, but be prepared to ask good questions for the position.

People are friendly, the office is amazing, and the offer is great. I declined because I had to pursue another similar opportunity, but it looks like an amazing place to work. Highly recommended for anyone interested in working in a challenging environment with smart people.

Writing an algorithm, explaining complexity, talking about edge cases, and making it thread-safe.