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v5.0.0

Svelte 5 Runes: A New Reactivity Paradigm

Svelte 5 introduces runes - a new way to declare reactive state that's more explicit and powerful.

January 17, 20254 min

Svelte 5 Runes: A New Reactivity Paradigm

Svelte 5 represents the biggest change to Svelte since its inception, introducing runes for explicit reactivity.

What Are Runes?

Runes are special symbols that tell Svelte how to handle reactivity:

svelte

Why Runes?

  • More explicit than implicit reactivity

  • Better TypeScript support
  • Easier to understand for newcomers
  • 50% smaller runtime

    Migration

    Svelte 5 includes a compatibility mode for Svelte 4 code, making migration gradual and painless.

    The Svelte team has delivered another innovative release.

    • Key Highlights

    • New features for developers
    • Performance improvements
    • Recommended for migration
    Note
    Before upgrading, we recommend reviewing the breaking changes in the official documentation.

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