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. Mobile-first or don't bother. Everything downstream followed from that.…