Svelte

What is Svelte?

Svelte is an open source UI framework that compiles components into small JavaScript modules instead of shipping a large runtime to the browser. It is maintained by the Svelte team and is usually paired with SvelteKit, the official application framework for routing, server rendering and deployment. The problem it solves is front-end complexity: reactivity, styling and transitions are handled by the compiler, so developers write less boilerplate and users download less code.

Key features

• Compiler-first design. Svelte compiles components at build time, which reduces the runtime work the browser has to do compared with frameworks that interpret components at run time.
• Runes reactivity. Svelte 5 introduced runes such as $state, $derived and $effect for explicit, predictable reactivity in components and shared modules.
• Scoped styles. Styles written in a component apply to that component by default, which avoids accidental cascade conflicts in large applications.
• Built-in transitions and animations. Transitions, animations and motion helpers are part of the framework, so common UI effects do not need a separate library.
• SvelteKit. The official app framework adds file-based routing, server-side rendering, prerendering, form actions and adapters for many hosting platforms.
• TypeScript support. Svelte components and SvelteKit projects support TypeScript, with editor tooling through the official language server.
• Accessibility checks. The compiler warns about common accessibility problems such as missing labels and invalid ARIA roles during development.

Who is Svelte for?

Front-end developers and full-stack teams building marketing sites, dashboards, content products and interactive web apps. It suits teams that want a small client bundle and fast interaction, developers who prefer writing close to standard HTML, CSS and JavaScript, and projects that need server rendering with a simple deployment model. SvelteKit makes it a practical choice for startups and agencies that want one framework for both static pages and dynamic apps.

Use cases

• Building a marketing site or blog with prerendered pages through SvelteKit.
• Creating an interactive dashboard with shared state and derived values.
• Adding animated transitions to a product interface without a separate animation library.
• Shipping a server-rendered app with form actions and API routes.
• Embedding small interactive widgets into an existing page.

Pricing

Svelte is free and open source under the MIT licence. There is no paid tier for the framework or SvelteKit, and teams can deploy to any host that supports static files or a Node server. See the official Svelte website and the SvelteKit documentation.

What's new

Svelte 5.57.3 was published on 26 October 2026. It fixed accessibility checks to use the first valid fallback role and corrected several hydration and state handling issues. Read the 5.57.3 release notes.

Getting started

1. Create a project with the official command line tool.
2. Move into the new directory and install dependencies.
3. Start the development server and open the local URL it prints.

npx sv create myapp
cd myapp
npm install
npm run dev

Alternatives

• Astro is a content-focused framework that ships less JavaScript by default.
• Nuxt is a Vue-based application framework with server rendering and routing.
• Vite is the build tool used by many front-end frameworks, including SvelteKit.

FAQ

Is Svelte free?

Yes. Svelte and SvelteKit are open source under the MIT licence, with no paid plan for the framework.

What is Svelte used for?

Svelte is used to build web interfaces. It compiles components into efficient JavaScript, and SvelteKit adds routing, server rendering and deployment support for full applications.

Svelte vs React?

Svelte compiles components ahead of time and does not ship a virtual DOM, while React updates a virtual DOM at run time. Svelte often produces a smaller client bundle with less boilerplate, while React has a larger ecosystem and more existing component libraries. The choice depends on team experience and ecosystem needs.

Do I need SvelteKit to use Svelte?

No. Svelte can be used on its own for components or embedded widgets. SvelteKit is the official framework for applications that need routing, server rendering, data loading and deployment adapters.

Does Svelte support TypeScript?

Yes. Svelte supports TypeScript in components and in SvelteKit projects, with official editor tooling for type checking and autocomplete.