Built out an entire web accessibility monitoring / scanning tool. The backend/scanning system required my knowledge as a programmer but the UI was entirely vibe coded. I said "build a UI for this scanning system on Cloudflare workers and use Hono.dev", and then just described in plain English how I wanted the UI to work.

Did this over a few weeks in my free time and now it has all of the features of accessibility monitoring SaaS that I was previously paying $600/mo for.