My name is Tomasz Czajęcki. I am a software engineer in Expo. I am originally from Kraków, Poland and currently live in Helsinki, Finland. Reach out on Twitter if you are around!

I love reinventing the wheel to figure out how things work. You can see some examples of that in my blog posts:

• How to Write a Flexbox Layout Engine
• Making Our Own Tiny Google Maps
• Understanding React by Implementing It

Short bio

I write most of my code in TypeScript and I am a big fan of the React ecosystem. I am most experienced as a frontend developer, but I often work on mobile apps, backends, CIs and sometimes infrastructure.

Technically I am sustaining myself by making money in developing software since 2015. Am I a professional developer with 8 years of experience?

I worked in Software Mansion between 2017 and 2020. For Rainbow Wallet in 2022. In Expo since December 2022.

I have done my master’s as a double degree in cybersecurity program called SECCLO in Aalto University in Helsinki, Finland and KTH in Stockholm, Sweden.

I used to be a huge fan of Haskell and functional approach in general, but nowadays I prefer simple and easy to debug and maintain code, which is often not the case with FP in JS. I strive to write code that I will be able to understand and fix in a year from now, in the middle of a night, woken up by a PagerDuty call.