Svelte is an open source framework for building web interfaces, created by Rich Harris in 2016, which works as a compiler: it turns components into optimized JavaScript at build time, instead of shipping a framework engine to the browser.
Components are written in files close to HTML, with simple logic blocks and CSS scoped to each component. The code sent to the browser is light and fast. Svelte 5 introduced runes, a reactivity model based on signals, which makes behavior more explicit in complex applications.
SvelteKit is the ecosystem's application framework (routing, server rendering, deployment), the equivalent of Next.js for React. Svelte regularly ranks among developers' favorite tools, but its adoption in companies remains well below that of React or Vue.
Why it matters when hiring
Hiring a pure Svelte profile limits the talent pool: strong front-end developers move from React or Vue to Svelte in a few weeks. It is better to look for solid JavaScript, CSS and server rendering fundamentals, then check curiosity for the tool. If the codebase predates Svelte 5, ask whether the candidate knows the migration to runes: it is a concrete piece of work.