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Comment by xiphias2 | Hacker News Reader

When I was applying to Coinbase, the interviews were heavily biased against people using low level data structures to write efficient code.

On my first interview I used C++, and it was very hard to pass their expectiations (the interviewer didn't know C++, so he couldn't appreciate the effort of me using a low level language).

I switched to Ruby for the next rounds, and got through easily.

Then I went to their beautiful office, I loved the people and the culture there, but didn't code fast enough to join the startup (which I'm happy about...startup mindset is not for me).

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> so he couldn't appreciate the effort of me using a low level language

I don't think impressing an interviewer is a good reason to pick a language for leetcode type questions..

I think it's all about whether you belong to a company or not. As I wrote, it's great that I wasn't accepted to Coinbase, as I wasn't a good fit (even though I was and still is a huge Bitcoin fan).

In another interview at a quant hedge fund I had a lot of fun talking to the interviewers (even the CEO) about low level data structures, and I got some tricky questions about the CPU that I really liked.

This sounds like a good thing for Coinbase IMO. An instinct to reach for low-level data structures and static typing to solve ambiguous or fast-changing business problems is usually a red flag for premature abstraction and sometimes also correlates with attitudes of superiority or looking down on other possible technology choices.

I don’t know if they treated you fairly or not, but the policy at least of appraising an instinctual reach for low level C++ as a negative sounds correct to me and should be a much more widely used heuristic in software hiring.

I was up with you in the first 1.5 sentences. Genuinely, I expected the comment to be about the need for very strict security in a financial codebase, and C++ is a known tool, that enables shooting yourself in a foot.

But then you started talking about static typing as negative, and suggesting to move fast and break things for a company, that probably hadles trillions in assets.

I opposed static typing because I favor safety, not oppose it. Type system designs prevent solving those problems.

Most of my career has been focused on helping large companies use Python to achieve as-fast-as-C performance with extremely little code and extremely safety-focused non-OOP software architectures, including in high frequency trading (where I built a company’s entire core trading platform in Cython).

The idea that static typing leads to safety is false. Static typing adds more code, more code is more liability. The cost of that liability is not recouped with any offsetting benefits.

I was specificially asking to work on the exchange trading backend, as that's what I was interested in. It was at a time when Coinbase was using javascript for the trading engine if I recall correctly (I think they moved to C++ since then, but not sure).

When I applied to a quantitative hedge fund, I was being asked questions about synchronizing data structures between threads without using mutexes (again not something you often do in a high level language). I was accepted there, although I couldn't go to work there because of health reasons.

At the end I went back to Google where I had to launch a new machine learning model without introducing even 0.1ms latency in the ads backend. Good luck doing that in a high level language.

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