After releasing the MVP of https://sheet2api.com around a month ago, I've been working on it most evenings & weekends adding Use Cases, fixing bugs, adding features. It was beginning to get to me the fact nobody was seriously using it yet.
The community here suggested I email all the users. When I did that, most ignored the email, 10% reported it as spam (👀) and a few replied, positively. One of those said they were very happy with it and showed me a website they were powering using the service.
That's the user that converted to a customer. So thanks for everyone here who suggested that. I'll continue with that route.
Even though it's a tiny amount of money, it's weird how one person signing up to an annual plan gives you a boost 👍.