4-9 years experience Excellent hands-on knowledge of HTML5, CSS3, JavaScript Hands-on experience working with Object Oriented JavaScript (OOJS), JavaScript - and practical uses in building complex interactive experiences, primarily with ECMAScript 2015+. You should be up-to-date with new specifications (different stages), and also, using transpilers like Babel to use features from all stages Good understanding of creational and structural design patterns in JavaScript Hands-on experience with Functional Programming (FP) Experience working with Single Page Applications (SPA) with universal rendering capabilities. Good understanding of React.js, its core principles - lifecycle methods, virtual DOM etc. and at least 6 12 months hands-on experience with the same