I applied online. The process took 2 weeks. I interviewed at Citadel Securities in Sep 2024
Interview
I had to first complete an online assessment of standard leetcode questions. No question was harder than a medium in my opinion. I was able to move on to the technical interview, where I talked with a Citadel Software Engineer but wasn't able to move on.
Interview questions [1]
Question 1
Before the Coding Question:
Q: What was one time you worked on a team project?
Q: What was one time you fixed a bug?
Then they asked the coding question, which was a medium leetcode like.
I applied through an employee referral. I interviewed at Citadel Securities (London, England) in Oct 2025
Interview
Pretty straightforward, some computer architecture. Good prep goes a long way for this in fundamentals. Know your CV and be able to answer a grilling, explaining design decisions. Fair sum of leetcode for others, but I got implementation-style questions more focussed on low level concepts (network protocols, allocation etc)
Interview questions [1]
Question 1
Why did you choose to use ___ (rare technology) in your last project/internship
I applied online. The process took 3 weeks. I interviewed at Citadel Securities (Singapore) in Sep 2025
Interview
The interview started with C++ trivia questions, which version I use and some features of it with internal implementations. The interviewer listened carefully to everything I said and we had good discussions. The coding question required quick thinking about which data structure would be best as per tc and sc.
I applied online. I interviewed at Citadel Securities
Interview
Started with a bunch of technical questions and follow up questions based on the previous answer.
Then only left 20 min for coding question (leetcode hard). It is pretty difficult.
Interview questions [1]
Question 1
implement ring buffer structure, write and read function
