Build a marketplace app without a technical co-founder

I'm not a developer. I spent eight months looking for a technical co-founder for a marketplace idea and got nowhere. Last month I stopped looking and shipped the thing myself. Posting the details because I wish someone had posted this for me a year ago.

The scope cut that made it possible

Every agency quote I got was $35K–$80K. Every one of them was scoping version 3 of the marketplace, not version 1. When I cut the feature list to the four things that actually matter — supply onboarding, demand discovery, connection, payment — the build got small enough for one person.

No reviews. No ratings. No in-app chat. No push notifications. No admin dashboard. All of those solve problems you don't have until people are already transacting.

The stack

UI: RapidNative — generates real React Native / Expo code from prompts. Free tier covered me for the first two weeks. Paid tier is $29/mo.
Backend: Supabase. Free tier.
Payments: Stripe Connect. Pay-per-transaction.
Builds: Expo EAS. $19/mo for the build tier.

Total first-month cost: ~$48 + Stripe fees.

The workflow

Landing page + waitlist on both sides of the market. 300 visitors driven through paid ads and 2 subreddit posts.
Manually brokered the first 6 transactions in a Google Sheet. This taught me more than the code would have.
Wrote a one-page spec naming both sides specifically.
Fed the spec to RapidNative as a prompt. Had a working native app on my phone via QR code in ~4 minutes.
Iterated by pointing at elements and typing what I wanted changed. Maybe 40 iterations total over 3 days.
Wired up Supabase auth + Stripe Connect Express. The AI scaffolded most of it. I pasted in the Connect onboarding URL by hand.
EAS build, TestFlight + Play Internal Testing, invited the waitlist.

9 days start to finish.

The numbers after 30 days

47 signups from waitlist (68% activated)
12 completed transactions
Match rate: 34%
30-day repeat rate: 58%
Avg GMV/transaction: $42
My take (15%): $76 total

Tiny revenue, obviously. But that's not the point. The point is I now know the flywheel spins. Before, I had a pitch deck. Now I have a working app, a 30-day retention curve, and two engineers who responded to my cold email this week.

What I'd do differently

Start the waitlist before building literally anything. I built to 80% before launching the landing page and lost two weeks.
Don't add chat early. Nobody cared.
Don't waste time on the admin panel. I have 12 users. I moderate by opening Supabase.

When you actually need an engineer

Past ~100 weekly transactions. Fraud detection, custom matching, real ops tooling. Recruit then. Not now.

Link to the tool: RapidNative

Happy to answer any questions in the comments — including the embarrassing ones about the 8 months I wasted looking for a co-founder.