I've been doing it manually: looking at resumes, code samples, and asking sample questions to judge for myself. Not sure there's any automated way to do that that will work any better.
My understanding was that you would vet open source contributors so they can support their own stuff. So looking at GitHub, commits, etc.
Otherwise your platform is really a way for random people to get money (nothing wrong with that) while the actual maintainers are busy writing code, reviewing tickets, etc.
I know monetizing open source is terribly difficult so I don't want to sound too negative.
You’ll also have the option to use customer feedback, if you think that makes sense.
Take a look at Lyft’s post-ride survey. Rate your ride, plus a set of chips that let people express what stood out about the driver, plus a comment field. Very simple & quick to complete.
Right now, the system works on a black and white "I was satisfied with this answer"/"I wasn't satisfied with this answer". If too many users note that they were continually unsatisfied with a particular answerer's answers, then I'm planning on handling that issue myself.
Otherwise your platform is really a way for random people to get money (nothing wrong with that) while the actual maintainers are busy writing code, reviewing tickets, etc.
I know monetizing open source is terribly difficult so I don't want to sound too negative.