Devin Entmacher · lifecycle marketer
I built a production fantasy football app in one week. Solo, with AI.
I'm a lifecycle marketer, not an engineer. Knife Fight is a last-team-standing fantasy football platform, live on the web and on iOS. AI wrote the code. Every product call stayed mine.
1 week
Zero to iOS
402
Commits
135
Merged PRs
161
Tests
Live
knifefight.io
iOS
On TestFlight
The tools don't make the product. Judgment does. AI collapsed the cost of building software. What it didn't touch is knowing what to build, sequencing it, and refusing to ship until it feels right. That part is product work, and it's the part I already do for a living.
01
What I shipped
four real product callsKnife Fight isn't a demo. It's a complete fantasy football platform. These are the four product decisions I'm proudest of.
01The lifecycle engineNineteen emails, each fired by a real moment, never a schedule.Read →02Live draft roomAutopick good enough that a room of real people lets it pick.Read →03The ScrambleWaivers rebuilt so when you spend beats how much.Read →04Public lobbyPublic leagues that fill themselves, with no cash prize.Read →
02
How I build
the method, in shortThree loops, one week. I direct all three and call when it's good enough.
ExploreLovableSketch a UI, react to something real, refine.
→BuildClaude CodeDirect it. Review every commit. Iterate.
→ReviewCodeRabbitCatch bugs. Fix what matters. Ship.