I've worked on a number of websites and Android apps. The websites I worked on mostly used the Spring Framework for backend but I can also make a fully functional backend in Node.js. I've used Backbone, React and Angular in the frontend. I've also been using Linux for the past 10 years. There's probably no way to prove that but I could fix/set up a bunch of things if you need some help. If that's not enough, I also have a master's degree in Computer Science, an Oracle Java 7 developer certificate and I have worked for a company as a Software Developer for about three years.