What does Svelte 5 Runes actually do?

Runes make reactivity explicit with $state for mutable vars, $derived for computed values, $effect for side effects — all compiler-tracked, TypeScript-first, no dep arrays.

Is Svelte 5 smaller than React for real apps?

Yes, in this landing page port: 61% gzip smaller. Scales to most apps via compile-time optimization, but test your own — runtime diffs shine on DOM-heavy UIs.

Should I switch my project to Svelte 5?

If bundle size or TS pains you, yes. Teams locked in React? Weigh migration cost. Start a side project; the demo GitHub awaits.

🛠️ Developer Tools

Svelte 5 Runes Port: 61% Smaller Than React [Bundle Breakdown]

Ever wonder why your React app's bundle feels like it's smuggling a small country? Svelte 5's Runes just ported a landing page to 18.92 kB gzip — 61% smaller than React. Here's the cynical truth behind the compiler win.

Open Source Beat Apr 14, 2026 4 min read

Svelte 5 Runes bundle size comparison chart showing 61% reduction vs React

⚡ Key Takeaways

Svelte 5 Runes ports deliver 61% smaller gzip bundles than React by compiling away runtime bloat. 𝕏
Explicit $state, $derived, $effect fix Svelte's old TS/module issues, feeling like plain JS. 𝕏
Compiler approach wins for small-to-mid apps, but enterprises may cling to React's ecosystem. 𝕏