Having wore that title before, it means "developer who is able to build a JavaScript application and bring it to production". For me, this included doing UX/UI

Having wore that title before, it means "developer who is able to build a JavaScript application and bring it to production". For me, this included doing UX/UI, the design, implementing web front-end (HTML, CSS, making sure it's responsive and optimized), the front-end business logic (Angular, React, Vue), setting up the server (typically the "back-end", either node.js or a more traditional approach like PHP), persisting to a database (like using MongoDB), managing APIs, etc. I am not a fan of the title "full-stack" (to me, that's just what being a developer is) but you need to wear it in order to get the right job offers and salary. For the longest time, front-end meant "HTML+CSS and a pinch of jQuery". So we need a title to break away from that trend.