There are people who have made lots of money with Fiverr - I wouldn't dismiss them right away. But for developers, there may be better options. I guess with sites like Fiverr, the trick is to come up with something unique which can also be automated (if not 100%) and just do batch jobs, for developers.

There are people charging good rates on Fiverr. One example here - https://www.fiverr.com/news/side-hustle-school and there are others.

They keep 20%, which stings :)