SvelteKit vs Next.js: A Practical Comparison

Two frameworks dominate conversations about modern web development: Next.js, built on React and backed by Vercel, and SvelteKit, the official application framework for Svelte. We've built production applications with both and developed clear opinions about when each excels.

This isn't a definitive "X is better than Y" verdict—both frameworks are excellent and actively maintained. Instead, this is a practical comparison based on real project experience to help you make an informed choice.

The Fundamental Difference

The core distinction isn't between SvelteKit and Next.js but between Svelte and React—the underlying UI libraries.

React uses a virtual DOM. When state changes, React creates a new virtual representation of the UI, compares it to the previous version, and updates only what changed. This reconciliation process happens at runtime, meaning React's runtime code ships to the browser alongside your application code.

Svelte takes a different approach: it's a compiler. At build time, Svelte analyses your components and generates minimal, imperative JavaScript that directly updates the DOM. There's no virtual DOM, no runtime framework code—just the precise updates needed.

This architectural difference flows through to SvelteKit and Next.js, affecting bundle sizes, performance characteristics, and developer experience.

Performance

In benchmarks, Svelte consistently produces smaller bundles and faster runtime performance than React. A typical SvelteKit application ships 30-50% less JavaScript than an equivalent Next.js application.

Does this matter in practice? It depends on your context:

For content sites: Initial load performance matters enormously for SEO and user experience. Smaller bundles mean faster Time to Interactive and better Core Web Vitals.
For applications with repeat users: After initial load, the difference diminishes. Cached bundles and progressive loading reduce the impact of bundle size.
For mobile users on slow connections: Every kilobyte matters. The difference between 100KB and 200KB of JavaScript is meaningful on 3G.

We've measured real-world performance differences on similar projects. A marketing site rebuilt from Next.js to SvelteKit saw Lighthouse performance scores jump from 72 to 96. Time to Interactive dropped from 2.8 seconds to 1.2 seconds. These aren't synthetic benchmarks—they're production sites.

That said, a well-optimised Next.js site can achieve excellent performance. The difference is how much effort optimisation requires and what your baseline is.

Developer Experience

Both frameworks offer excellent developer experiences, but they feel quite different in practice.

Svelte components feel like writing enhanced HTML with bits of JavaScript. The syntax is close to vanilla web technologies. There's no JSX, no hooks rules to remember, no choice between class and function components. State is just reactive variables.

React has a more programming-centric feel. JSX is JavaScript with HTML-like syntax, not the reverse. The hooks system is powerful but has a learning curve and pitfalls around dependencies and closures.

For developers coming from traditional web development (HTML, CSS, vanilla JavaScript), Svelte often feels more intuitive. For developers with programming backgrounds, especially those familiar with functional programming, React's model may feel more natural.

Hot module replacement is faster in SvelteKit in our experience. Changes appear in the browser more quickly, and state preservation during development is more reliable. This matters for productivity—fast feedback loops encourage experimentation.

Ecosystem

React's ecosystem is massive. Whatever component you need—data tables, charts, date pickers, rich text editors—there's likely a React implementation. The sheer volume of packages, tutorials, and Stack Overflow answers is unmatched.

Svelte's ecosystem is smaller but growing. Core needs are well-covered, but for specialised components, you may need to build your own or adapt vanilla JavaScript libraries. This is usually straightforward since Svelte works well with standard JavaScript, but it's more work than installing a ready-made React package.

For enterprise applications needing extensive third-party integrations, React's ecosystem is a significant advantage. For projects where you're building most functionality yourself, the ecosystem size matters less.

Framework Features

As meta-frameworks, SvelteKit and Next.js have converged on similar feature sets:

Both support static generation, server-side rendering, and client-side navigation.
Both offer file-based routing with dynamic segments and catch-all routes.
Both provide API routes for backend functionality.
Both support layouts and nested layouts.
Both handle code splitting automatically.

SvelteKit's form actions provide elegant progressive enhancement—forms work without JavaScript and enhance when it's available. Next.js has server actions, which are similar but feel more tightly coupled to React's model.

Next.js has had longer to mature, and some advanced features like ISR (Incremental Static Regeneration) are more polished. The App Router (introduced in Next.js 13) brought significant architectural improvements, though it also brought breaking changes and a learning curve for existing Next.js developers.

Deployment

Both frameworks deploy easily to Vercel, as you'd expect since Vercel backs both frameworks. But flexibility extends further:

SvelteKit's adapter system lets you deploy to Node servers, serverless platforms, edge functions, or static hosts. Switching deployment targets is a configuration change, not a rewrite.

Next.js works best on Vercel but supports Node deployments and static export. Some features, particularly around caching and incremental builds, are tightly integrated with Vercel's platform.

If you need to self-host or use non-Vercel infrastructure, SvelteKit's deployment flexibility is advantageous.

Team Considerations

If you're hiring developers or building a team:

React developers are more abundant. Hiring React experience is easier; more candidates know it. If you're a startup needing to scale quickly, this matters.

Svelte is generally faster to learn. Developers productive in weeks, not months. If you're training team members or working with developers new to modern frameworks, Svelte's gentler learning curve helps.

React experience is more transferable. Skills transfer across React Native, React-based tools, and the broader React ecosystem. If developers may move between projects using different technologies, React experience has broader applicability.

That said, developers who know one framework can learn the other. The concepts transfer—it's mostly syntax and conventions that differ.

Our Recommendation

For most projects we undertake—business websites, eCommerce frontends, content platforms—SvelteKit is our default recommendation. The performance advantages, developer experience, and deployment flexibility align well with typical requirements.

We'd recommend Next.js when:

The project requires extensive React-ecosystem integration (specific component libraries, React Native code sharing).
The team has deep React expertise and limited capacity to learn new frameworks.
The project is joining an existing React codebase.
Specific Vercel platform features (like ISR or on-demand revalidation) are central to requirements.

Both are capable frameworks backed by strong organisations. You can build excellent applications with either. The choice often comes down to team context and project-specific requirements rather than objective superiority.

If you're starting a new project and unsure which direction to take, get in touch. We're happy to discuss your specific requirements and recommend the approach that best fits your situation.