Quantitative Developer Interview Guide

What is a Quant Developer?

The role of a Quant Developer, sometimes referred to as Financial Engineer, has become increasingly important with advancements made in technology and mathematical finance.

As computing systems have become faster, it has been possible to implement mathematical models that were previously considered too complex to be computed by machines in a reasonable time frame.

This has led to an increasing need for researchers and analysts who had a solid understanding of computer science principles to bridge the gap between the technology and the mathematics of our pricing; this is where the quant developer comes in.

What does a Quant Developer do in Mako?

First and foremost, being a quant developer at Mako means being part of the Software Engineering team, but the breadth of your role will be far wider than that. You will spend the majority of your time coding in a collaborative and stimulating environment, helping us to solve a broad spectrum of challenging problems.

You will also have the opportunity to work together with Traders and Quants on Mako's numerical challenges and algorithms. Your expertise will help us develop new ideas, extend our existing mathematical framework and optimize the existing code for maximizing throughput.

Technical Skills

You are expected to have a genuine interest in the following:‍

• Mathematical Finance: stochastic calculus and non-arbitrage asset pricing models
•  Numerical Simulations: discretization techniques and optimization problems,
• Software Engineering: represent data in the most performant way and never be satisfied with O(N²) complexity

You are not expected to be proficient in all of this, but your job as a Quant Developer will revolve around these concepts.

What to expect during the interview?

A Quant Developer interview generally lasts about 1 hour.

Be prepared to guide the interviewer through your CV, emphasizing the most relevant experiences. A good presentation is often the perfect starting point.

The first skill that is tested is the ability to solve problems you have not encountered before: the quickest way to demonstrate this is to show how you solve brain teasers.

Secondly, you will be asked to work on a problem you would have likely encountered before: you need to demonstrate that you have the right knowledge arsenal at your disposal and that you know how to navigate in familiar waters.

Lastly, the interview is a research process for both parties: Mako is looking for the ideal candidate, as much as you are looking for the ideal company to work for. Make sure to understand what Mako is offering and whether or not that’s what you’re looking for.

What to do before the interview?

Interviewing as a Quant Developer is challenging. A lot of practise is required for improving your success rate.

Brain Teasers

Make sure you have pen and paper ready. Remember: showing how you reached your answer is more important than arriving at the right one. Sometimes there's more than a single correct answer and it's easy to follow an approach that leads to a dead end. Don't be afraid to take a few steps back and restart, you are valued on how well you solve a problem, not on the number of attempts you've taken before finding the solution.

Here are a few tips:

• Don't be afraid to ask questions: asking the interviewer can only help if you haven't fully understood the problem.
• Think out loud: unless you've already seen that specific brain teaser, no one is expecting you to immediately come up with the correct answer. Make sure you eloquently show why and how you are exploring the space of the potential solutions.
• Take your time: brain teasers don't test your knowledge on a particular topic, therefore it's perfectly fine to reorganize your thoughts before rushing to a possibly wrong answer.
• Put your thoughts on paper: being able to analytically describe the problem generally helps, and it can help your brain to come up with a structured answer.
• Induction is your friend: sometimes it helps to find a pattern. There's no need for you to provide a mathematical proof by induction, but if you can show that a pattern exists for a smaller sized problem it will help you engineer the solution quickly.

Here are examples of what you are not going to be asked:

• The “how many” brain teasers: e.g. “How many petrol stations are there in the UK?”
• The “describe yourself” questions: e.g. “If you were an animal, what would you be and why?"

Knowledge-based Questions

At this stage, you are asked to show how well you can apply your theoretical knowledge to solve a familiar problem. These are closer to real world problems than brain teasers,and they are usually a slight variation to a well-known problem.

This is not a memory test, as we are interested in seeing how you can find a solution, not if you remember some tiny details from your degree.

The most frequently asked questions in the industry are in the following areas:

• Numerical Analysis
• Partial Differential Equations
• Monte Carlo simulations
• Linear Algebra

You should already be familiar with all of these, and if you are not, make sure you brush up on these topics.

Coding Problems

A consistent part of your interview at Mako is a live coding test. You will be asked to design algorithms that solve a certain class of problems in the most efficient way. Check our blog post on software development interviews here for more information.

Mako uses C++ as our main coding language. But the most important aspect is that you understand the object oriented paradigm.

Cultural Fit

You will likely be a successful candidate if the answer to the following questions is positive:

• Are you a good team player?
• Are you intrigued by solving puzzles?
• Do you genuinely like maths and coding?
• Can you work under pressure?

Why Apply Now?

Being a Quant Developer at Mako entails working on a multitude of challenging tasks and engaging in fascinating technical debates with traders and developers, all whilst being part of a fun, collaborative and inclusive environment. Check out our current openings if you think you have what it takes to be a successful candidate.

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