These are pretty great and it looks like an interesting project, but why "4+ years of experience"? First of all, what exactly is a "year of experience"? You spent the entire year using some piece of tech? You used the tech once a year ago? I hate how commonplace these sorts of non-verifiable claims are in job postings.

Edit: I've been thinking about this some more and perhaps "hours of experience" is a better metric, given the 10,000-hours-to-mastery correspondence.