I convert PSD to HTML and PSD(Mobile) to real world apps, using React and React-Native. I mostly use styled-components combined with SCSS for styling.
I use React to make web apps with the use of cutting edge technologies and work with latest features such as hooks, context and so on. I have also worked with GraphQL.
I would say, App Development is my area of expertise. I have over 2.5 years of experience in App development using React-Native. I work with cli, expo, code push and much more.