I run HTTP Toolkit ( https://httptoolkit.com ) which passed $2k a couple of years back. No longer a side project, as it's made enough money for me to work on it full time for a fair while now, but it certainly started that way, and it's still a one-man show (plus many wonderful open-source contributors). I suspect that'll be a common theme in answers here though: if you have a side project making $2k a month, in most…
I was just about to ask how do you differentiate your product from mitmproxy but on a quick google search I found this thread from a few years ago: https://news.ycombinator.com/item?id=29627819