[_asciiker_]

I've launched Sentopia (https://www.sentopia.net) as a side project and it is still easily making over 1K with just 2 medium sized clients but it is not passive income, requires some maintenance & customer support but still very much worth it.

This year we're launching new features and a simple API: (https://sentopia.net/apidoc/)

[marktangotango]

Very nice, what did you use to generate your api docs?

[_asciiker_]

Thank you! I used apiDoc (http://apidocjs.com/)

[maxsavin]

Are you trying to grow beyond the two clients?

[_asciiker_]

There are more than 2 :) But since most use the free plan, the 2 I was referring to make up almost 80% of the monthly income.