Solo-Founding the Engineering Side of a Rental Startup: What I'd Do Differently

Being the only engineer on a product means every tradeoff is visible and every consequence is yours. This isn't a highlight reel — it's what I'd actually change, looking back at Amber Car Rental so far.

What breaks first when you're solo

Not the code — the queue. Customer coordination, admin dashboard requests, and a genuine architecture decision all show up on the same day, and there's no one to hand any of them to. The failure mode isn't "can't do the work," it's context-switching cost eating hours that should have gone to the hardest problem of the day.

What I'd do sooner next time

• Write the admin-side runbook earlier — the first few weeks of "just ask me" don't scale even to a two-person team, let alone a client's own staff.
• Add the database-level booking constraint from day one instead of after the first near-miss. It's cheap early and expensive to retrofit once real data depends on the old, looser behavior.
• Set a lighter cadence for client updates from the start — a solo developer under-communicates by default because there's no standup forcing it, and clients notice.

What I'd repeat without changing

Choosing Supabase over a hand-rolled backend, and leaning on AI-assisted tooling instead of trying to do everything by hand. Both decisions bought back hours that went directly into the parts of the product that actually needed a human's judgment — the booking rules, the admin workflow shape, the client relationship.