A software engineer at Swarmia. Living in Helsinki, Finland. Previously, I worked at Unity.com, and Thoughtworks.https://heyfirst.co/https://heyfirst.co/posts/done-on-paper-before-done-in-code/https://heyfirst.co/posts/done-on-paper-before-done-in-code/How I plan a work before starting to code with Technical Design Document (TDD), Or so many people called it as Request for Comments (RFCs) and Design DocsSat, 06 Jul 2024 00:00:00 GMThttps://heyfirst.co/posts/helsinki-tallinn-guide/https://heyfirst.co/posts/helsinki-tallinn-guide/I've lived here 4 years in Finland, and everyone keeps asking me for the same guide, thus this blog!Fri, 10 Jul 2026 00:00:00 GMThttps://heyfirst.co/posts/how-to-use-test-todo-in-jest/https://heyfirst.co/posts/how-to-use-test-todo-in-jest/Heyo! I learn a cool thing when I do pair programming with my teammate. It's about writing Jest tests in a more make sense way. Let's talk about it!Tue, 03 Aug 2021 00:00:00 GMThttps://heyfirst.co/posts/how-we-estimate/https://heyfirst.co/posts/how-we-estimate/Have you ever struggled with estimating software project timelines accurately?Tue, 16 Apr 2024 00:00:00 GMThttps://heyfirst.co/posts/i-built-my-first-pc/https://heyfirst.co/posts/i-built-my-first-pc/A July side-project from someone who wants to play gamesSun, 03 Aug 2025 00:00:00 GMThttps://heyfirst.co/posts/micro-dollar/https://heyfirst.co/posts/micro-dollar/The easiest way to deal with decimal number in our application is multiply by 1,000,000. such that using 6-digit decimal you won't make a mistake.Tue, 07 Feb 2023 00:00:00 GMThttps://heyfirst.co/posts/stacktrace-is-underrated/https://heyfirst.co/posts/stacktrace-is-underrated/I found something cool about stacktraces that I think you'll find really useful! They're not just for errors anymore.Sun, 10 Aug 2025 00:00:00 GMThttps://heyfirst.co/posts/the-interview-insights/https://heyfirst.co/posts/the-interview-insights/Untold story from another side of the chairTue, 11 Mar 2025 00:00:00 GMThttps://heyfirst.co/posts/write-ahead-log/https://heyfirst.co/posts/write-ahead-log/A write-ahead log is just writing down the step before I run it. Same trick shows up in Postgres, and in how Cursor hosts Git.Sat, 29 Aug 2026 00:00:00 GMT