Interview with Jonn Mostovoy Co-Founder at Serokell
Hayden - Nice to meet you, firstly I’d like to thank you for taking the time to complete this interview, I really appreciate it! I’ve taken some time to research your background & experience, as well as Serokell, but for the sake of context, would it be ok for you to introduce yourself & the company in your own words?
Jonn - Thank you for having me! I started programming because in my school there were a lot of people who were attending an extracurricular club called “fortech”, which was later renamed to “progmeistars”. The first language I used to build real systems was PHP, bundled with easyPHP bundler for Windows. I started selling my software while studying in high school, then got hired into a software development company https://very.lv, which was making a social network for professionals for the Russian-speaking market. We had to scale from zero to tens of thousand unique users to a million. It was an instrumental experience in industrial programming. I first started learning Haskell while at very.lv, because my colleague looked at my PHP code and said that I should check it out. Afterwards I worked in banking software using C# and Linq, which enabled me to use some of the aspects of functional programming in an industrial environment. When I got tired of the “bloody enterprise”, I switched gears to startups. Having a decent experience with solving a wide range of problems in Erlang language, I caught a wave of mass exodus of node.js projects switching to Erlang, thanks to Facebook hype. I managed to position myself well in the market and that’s how I started to get my first senior / tech lead positions. Then, over the course of three years, I saved enough money and practiced enough Haskell to implement my dream. With a friend of mine with whom we met on #nixos channel in IRC, we have co-founded a Haskell consultancy and an outsource company called “Serokell”. We have implemented several interesting systems: a secure linux distribution, a bitcoin exchange, and then we got hired by IOHK to implement the settlement layer of their cryptocurrency and bootstrap their genesis block. It was a ton of fun and we’ve done it successfully under quite a time pressure. Now our primary focus is biotech and data science, but involvement in blockchain projects still remains rather great. We regularly perform security audits of smart contracts and develop a huge chunk of the Tezos ecosystem -- from Tezos Agora (the main coordination website for everything Tezos, with blockchain integration) to ergonomic programming languages for Tezos Smart contracts. As you can imagine, Erlang and Elixir are very much used by us and me personally. Our product, https://pont.ee, has an Elixir backend, which coexists with Haskell workers, and I have recently implemented a verifiable credentials framework in Elixir as a pet project.
Hayden - Thank you, that’s a great introduction! I’ve read some of the case studies on your website, it seems you have some recent success stories of building successful crypto-focused platforms in Haskell, you may have seen our interview with Kamil Skowron in which he discussed building a Crypto engine in Elixir, could you tell us a bit about why you opted for Haskell? How do you feel about approaching a similar project in Elixir? Jonn - Yes, I’ve seen the interview! It’s nice and succinct. Not many know, but the first version of Cardano settlement layer could have been implemented in Elixir! That said, most of our projects are full stack, and especially something like CSL, where we want to run the node, the wallet middleware both on servers in headless mode, and on the clients’ laptops with UI attached. After performing a TRL review (technical readiness level), we have decided that Haskell would be a correct choice for such systems’ topology. We also took into account the fact that the volume of purchased tokens by the time we have started the development was already insanely huge, so compile-time guarantees for the ledger state maintenance was amongst the key factors. That being said, we’ve participated in amazing projects that use Elixir in the blockchain space, for instance, we’ve helped to optimise and refactor POA’s Ethereum block explorer! For things like that, Elixir and other BEAM languages work really well.
Hayden - Interesting to hear the thought process behind choosing a specific language.. seeing as you offer a range of functional programming expertise as a USP at Serokell, what does your criteria generally look like for hiring?
Jonn - It’s a tough one! We rarely look for unicorns, we normally hire Haskellers who can learn and hope they will be OK with working on non-Haskell projects. We also hire polyglot developers who are willing to read and write some Haskell, this way we can onboard customers that need, say, Rust or Go easily. Finally, as I mentioned, https://pont.ee is built with Elixir, and since we also use it as an internal tool, we hire BEAM developers to develop it and that allows for rotation of Elixir developers to work for our customers when such need arises. Our HR department is always busy and they are heroes for dealing with the amount of technologies we use daily. Hayden - How do you assess that in an interview process? Are there any challenges related to doing that remotely?
Jonn - We have a system of automated and semi-automated test tasks, carefully tailored to our business needs and heavily inspired by Matasano hiring strategy. The interview process then is a dialogue between the tech lead that shall be responsible for the new team member and said team member to figure out their preferences and understand the best fit for the new team member. We are remote-first (essentially, “remote” as in GitHub 1.0) since conception. Nothing is an unbeatable challenge to go remote for us. As a matter of fact, I met the co-founder of Serokell for the first time when we were submitting papers related to starting the company in Estonia. That being said, we know that some things about remote working cause friction, but we help our team members to cope with it.
Hayden - I noticed from your Github that you have been interested in Elixir for some time, how were you introduced to it? What’s your overall impression of the language, compared to others you’ve worked with?
Jonn - I have been introduced to Elixir by Yurii Rashkovski, with whom we were working as contractors for the same company all the way in 2012/13. We figured we’d use Elixir for some of the work we were doi