Architecture decisions, cost breakdowns, and engineering lessons from building SaaS platforms for funded startups.
In January 2022 we packed five 3D printed computers into a box on a kitchen table in Osijek and posted them to a gym franchise in Australia. Everything we got right and everything we got wrong came from one fact: none of us would ever see those machines again.
QuizUp had 100 million users and shut down in 2019. Years later its subreddit was still active, full of people who missed it. Quizzy was built for them, and the hardest engineering problem came directly out of that grief.
Translated speech is rarely the same length as the original, and in a 30-second ad that difference is the whole problem. Here is the pipeline we built, plus the bug I found in my own code while writing this up.
A gym class where every wall-mounted screen has to show the same frame at the same instant. Here is the clock synchronisation, why round trips make it genuinely hard, the decision to replace the global Date object, and how a CMS ended up choosing our hardware.
Three production applications, one Firebase project, a monthly bill of zero. Then we deleted the entire frontend and rebuilt it in a different framework, and the number did not move. That is the actual argument.