I deleted every fitness app I tried. So I built my own — in 17 days, after work.

I'm a back-end developer in Korea.

Nine years of Java, Kotlin, and Spring — all of it building other people's servers. Until last month, there wasn't a single app with my name on it in any store.

That changed in 17 days: 172 commits, 30 database migrations, 5 languages. A fitness and diet app called Baanbok — it's Korean for repetition. It's live on the App Store now, and currently fighting its way through Google Play's closed-testing gauntlet (a mandatory 14-day gate — 5 days to go).

The numbers make it sound like a hackathon story. It wasn't. I have a full-time job. I just opened my laptop every evening after work and stacked a little more on top of yesterday's pile.

This series is the log of those 17 days. But honestly, the story starts three years earlier.