At 8:47 p.m., I ran out of bedtime story ideas.

My kids wanted one more story about their preferred characters, my grandpa. But this time my brain just want to go offline.

I thought I shouldn't be alone with this problem, so since I'm a builder, I started thinking of a solution.

I decided to build the thing I needed to create engaging stories for my kids when I'm not in the mood of telling the stories by myself.

This little idea became Lumio — a personalized AI bedtime story app. This post is about the product decisions and how I built it.

The constraints that actually shaped the architecture

Before picking any tech, I had one hard constraint: I am a solo developer with multiple projects and as you can tell I have kids that demand great stories:

No separate mobile codebase. I will not maintain two story experiences.

No "we'll figure out mobile later." Parents live on their phones.…