I've been working on the same business since 2021:

https://notionbackups.com

The first business I started never gained traction, so I sold it in 2021 (which was a completely different time compared to now).

Notion had announced that they'd launch a beta version of their API, so while waiting for the early access, I built a landing page, login/signup, and all other plumbing for the web app.

It was a rather underwhelming launch (both for the API and my business), but I gained my first customer within a month.

Honestly, it's been a slog running this business (Notion's API is surprisingly hard to work with, so it seemed that I was stuck for months on end), so knowing what I know now, I'd probably have started a different business. My burnout didn't help either.

Claude has been incredibly helpful these last few months in solving esoteric undocumented edge cases that were plaguing the codebase for years.

I have a healthy MRR/growth rate right now and the biggest product in the niche, so I'm grateful for that.