I interview lots of people for my current and previous employers. I primarily look at public git repos, carefully reading their code. Bonus points for continuous education (Coursera, eDx, etc.). Ultimately though success is also strongly driven by being good at getting along with people, having a habit of carefully reading coworker’s emails and documents, and writing skills. Work is a mixed bag.

I would definitely list online classes and certifications on your resume, right below where you list your public git repos.