How to build a side project with a full-time job (and kids)

Fixed windows, not stolen hours. That's the whole system. I build from 9 to 11 PM on weeknights, on Saturday mornings when the house is quiet, and on lunch breaks that aren't meetings. Six products have come out of those margins, alongside a full-time job in security and two kids. Nothing about it requires waking up at 5 AM or believing in yourself harder.

Why fixed windows beat motivation

A stolen hour needs negotiation — with your family, your sleep, your guilt. A fixed window needs nothing. By 9 PM the kids are down, the day's obligations are settled, and nobody else has a claim on the time. When the window opens, I don't decide whether to build. The deciding was done months ago. That removes the tax that kills most side projects: renegotiating with yourself every single night.

Scope like your hours are the truth

The windows yield around 13 hours a week. So I build small products that can reach users in weeks — a burnout assessment, a couples habit tracker, a parenting assistant — instead of one grand platform that would still be a prototype two years in. Six small shipped things beat one big unshipped thing: users, feedback, momentum, proof. If you want the actual timelines, they're in how long it takes to build an app with AI.

Let the tools fit the window

AI coding made two-hour windows worth something. With Claude Code I describe the next piece in plain language, get working code, and test it before the window closes — vibe coding, in practice. Two hours used to be barely enough to remember where I left off. Now it's enough to ship a feature. For people with jobs, that's the real change: the minimum useful session collapsed from an afternoon to an evening.

The family part, honestly

The build happens after bedtime because bedtime is non-negotiable and the build isn't. Saturday mornings work because the house is asleep, not because I'm disciplined. Some weeks produce nothing — kids get sick, the job eats the evenings, the tank is empty. The system survives those weeks because it never depended on streaks. It depends on the window still being there next week.

The consistency math

Two hours a night doesn't sound like much. Kept up, it adds up to 500-plus hours a year without touching your job, family dinners, or weekends together. Most people don't need more time. They need the modest amount they already have to stop being up for debate every night. That's the whole premise of Second-Act Builders — and if you're wondering whether it works without a technical background, that answer is here.