A little (more) about myself and how I ended up at Jane Street

Hi there! My name is Andrei. One year ago, I graduated from my 3-year Bachelor’s degree in Computer Science at Babes-Bolyai University of Cluj-Napoca, Romania. At the moment, I’m currently pursuing a Master’s degree (in Computer Science as well) at the U.S.-based University of Illinois Urbana-Champaign as a remote, part-time student, while also working full-time as a software engineer at Bloomberg in London.

However, to better understand my context and how I ended up like this, I would like to take you back to my primary school years, because my passion for software engineering began long before my formal studies. As a kid, I loved creating things, whether it was drawing or building with LEGO. At the same time, I was always drawn to science subjects in school, especially math. That all came together when I discovered computer science in the fifth grade, which gave me a unique opportunity to make the most of both worlds and combine creativity with the precision of the exact sciences.

Unfortunately, throughout my computer science school years, the focus was almost entirely on competitive programming and participating at Olympiads and various competitions. While it was fun to a certain extent, and definitely helped me build a strong foundation for future interviews, I always knew that software engineering was about more than just algorithms. That’s why during high school, I started exploring and learning a lot on my own, from building a bunch of side projects (like a gamified social media web application dedicated to saving the environment) to even working as a freelancer for a few months and building “real projects” used by real people.

University and First Internships

Fast forward a few years, university was where I really began to fully understand the fundamental principles of computer science. One of my biggest pieces of advice would be to approach almost every course with seriousness and dedication, because even though it might seem useless at that time, the knowledge you gain is essential for your future professional career and interviews (I know it was for me).

During the summer after my first year of university, internships weren’t mandatory, but I was eager to gain hands-on experience, learn more, and, why not, maybe earn a bit of money too. Although I was at a disadvantage compared to students in higher years, I started applying to various companies listed on my university’s website. Naturally, I aimed high, targeting big tech companies like Google, but my mistake that year was starting too late — by spring time all the big tech companies would have rounded up their internship lineups. Fortunately, I still managed to land an fully-remote internship at a smaller U.S.-based company that also had an office in my university town. The experience was great, don’t get me wrong — I learned a lot and enjoyed the company culture, but my dream was still to work at one of the big tech firms.

The Grind and The Unexpected Offer

Because of that, I began applying for next summer internships while I was still working at my first one. I spent my summer working full-time, and in the evenings or weekends, focused on grinding LeetCode, solving problems, polishing my resume and refining my behavioral interview skills. This consistent effort didn’t stop when university started and continued into the beginning of my second year. I knew that if I didn’t secure an offer by winter, I’d likely have to settle again for local internships.

And there I was — applying to nearly 100 internships, mostly found through platforms like Levels.fyi and Reddit and completing dozens of online assessments and interviews. At the time, my focus was mainly on big tech companies (the FAANGs), and I wasn’t even familiar with trading firms like Jane Street. Still, that didn’t stop me from applying to those companies as well.

My experience with Jane Street was quite interesting. I had applied to one of their software engineering internship positions after hearing about the company from a high school friend. This was back in autumn. The first interview was a technical one with one of their engineers, but unfortunately, I was rejected. Still, life goes on … I had dozens of other applications in the pipeline at the time.

However, by February, I was starting to feel a bit desperate. I still hadn’t secured any major internship. I had an offer from Amazon, but it was frozen due to a hiring pause, and a few other offers from smaller, local companies. Then, out of the blue, I received an email from Jane Street. Although I had been rejected for the software engineering internship, they were inviting me to the final round of interviews for their production engineering internship. At the time, I still didn’t fully realize how prestigious Jane Street was. I even considered turning it down, but I figured, why not give it a shot?

The final round consisted of three back-to-back interviews with short breaks in between, resulting in about 4–5 hours of full concentration and stress. Two out of the three interviews were highly technical, similar in spirit to LeetCode problems, but more abstract and complex. The emphasis was on how cleanly you structured your code and explained your thought process, rather than how well you had memorized certain algorithms. The third interview was more practical and fun, focused on testing my investigation and debugging skills through a simulated production issue.

The interview process was tough, and I was completely exhausted by the end of it. But that evening turned out to be one of the best, because not only did I receive an offer from Jane Street, but Amazon informed me that their hiring freeze had been lifted. Just the day before, I had nothing outstanding lined up, and suddenly I was choosing between two major companies.

The Internship Experience

In the end, I chose to intern at Jane Street. As they describe themselves: “Jane Street is a quantitative trading firm and liquidity provider with a unique focus on technology and collaborative problem solving.” (TL;DR: they use math, code, and a lot of brainpower to help markets function more efficiently and make lots of money.)

The internship was based in London over the summer, and fortunately, Jane Street provided us with accommodation just 15 minutes away from the office. Since this was post-Brexit, I needed a visa, but Jane Street fully supported me throughout the process, making it as smooth as possible.

As a production engineer intern, my role was a bit different from that of a typical software engineer. While I spent a good amount of time coding and building infrastructure systems, the first half of my day was focused on on-call support. What does on-call support mean? It involves monitoring the health of the systems and the trades happening in real-time, and proactively resolving any issues or errors that come up.

A typical day started with me waking up at 7 a.m. and getting to the office around 8–8:30. I’d have breakfast with other interns for about 30 minutes, then head to my desk and start my on-call shift. Around lunchtime, we’d hand over support to the New York team as their workday began. After that, I’d grab lunch with my team (the company provided meals) and continue working on longer-term projects in the afternoon.

Evenings were always dynamic. I usually stayed at the office until 7 or 8 p.m. — not because I was working the whole time, but because there was always something interesting going on: poker classes, guest speaker talks, chess tournaments, or team dinners.

Overall, the experience was amazing. I grew a lot, not just professionally, but personally as well.

Preparing for Interviews

Preparing, applying, and interviewing is a job in itself. It’s tedious, demanding, and requires a lot of discipline and focus. One resource that really helped me throughout this process was the Tech Interview Handbook. It covers in great detail what you need to prepare for tech interviews. But to break it down simply, I focused on these three main areas:

1. Getting good at solving programming problems

Grinding LeetCode helped a lot. But one common pitfall many people fall into is memorizing the problems instead of understanding the underlying patterns. In real interviews, you’re unlikely to get the exact same question — but you might get something similar. Recognizing the type of problem and applying the right strategy is what matters.

I also found it useful to:

• Read solutions afterwards.
• Try solving the same problem using different approaches.
• Practice explaining my thought process out loud, as if I were on a call with a real interviewer.

Even if you don’t reach the final answer during an interview, how you communicate matters a lot. Practicing this out loud helped me a ton. And if you have friends with more experience, asking them for mock interviews can really elevate your prep.

2. Polishing my resume

My resume went through many iterations. It’s important to carefully think about:

• What you’ve achieved
• What you want to highlight
• How to tailor it to each job application

I know it’s tedious, but ideally, you should customize your resume for each job. Use the keywords and language from the job description. If something isn’t relevant or mentioned in the posting, it probably doesn’t belong on your resume.

Structure your bullet points using the “Achieved X by doing Y, resulting in Z” framework — and make sure to emphasize the “Z”. Metrics and measurable impact are key.

3. Preparing for behavioral interviews

This part is often underestimated, but it’s just as important as technical prep. I made sure to prepare 10–15 stories from my professional or academic experience, each focusing on different strengths (e.g. leadership, teamwork, conflict resolution, resilience, etc.).

Use the STAR framework:

• S – Situation: set the context
• T – Task: what you were responsible for
• A – Action: what you did
• R – Result: what the outcome was (ideally with metrics)

Being structured and specific in your responses helps interviewers clearly understand your experience and impact.

Final Thoughts: Advice from My Internship Journey

Before Applying

• Get involved. Side projects, hackathons, extracurriculars — they matter. What you learn in school is important, but it’s often not enough to stand out.
• Stay curious. Explore topics beyond your coursework. You never know what skill or interest will give you an edge later in your career.

When Applying

• Don’t get discouraged. Rejections are part of the process. Talk with friends, vent if you need to — but don’t isolate yourself. I made that mistake, and it didn’t help.
• Luck matters. It’s a numbers game. That said, you still need to be ready. Luck might get you the interview, but skills and preparation close the offer.
• Think outside the box. Cold-email recruiters, message people on LinkedIn, ask for referrals — you’d be surprised how often it works.
• Apply internationally. Don’t limit yourself to one country. If you get the offer, you can figure out the logistics later. The “admin stuff” is solvable.

During the Internship

• Focus on the people, not just the work. Build good relationships with your team. In the long run, they may forget the exact code you wrote, but they’ll remember how it felt to work with you.
• Be proactive. Take initiative. Don’t wait for your mentor to tell you every step — take ownership of your project and show that you care.