SvelteKit 3 goes alpha with bundler shifts and tougher requirements

SvelteKit 3: the path forward

This week SvelteKit took a big step toward its next major version with the release of @sveltejs/kit@3.0.0-next.0 and an accompanying suite of adapter pre-releases. The core framework bumps minimum requirements to Node 22 and TypeScript 6, upgrades to cookie v1 (which restricts cookie names to ASCII characters), and removes the preloadStrategy option in favor of always using modulepreload. A follow-up 3.0.0-next.1 patch restores the $app/environment alias for compatibility with dependencies that still import from the old path.

Perhaps more consequential than the framework changes themselves are the shifts happening in the adapter layer. @sveltejs/adapter-node@6.0.0-next.0 and @sveltejs/adapter-vercel@7.0.0-next.0 both swap Rollup for Rolldown as their bundler, with the Vercel adapter targeting es2022 for edge functions. @sveltejs/adapter-netlify@7.0.0-next.0 additionally aligns with the stable Netlify Frameworks API, meaning deployments now require Netlify CLI v17.31.0 or later. @sveltejs/adapter-cloudflare@8.0.0-next.0 upgrades @cloudflare/workers-types and replaces platform.context with platform.ctx. Meanwhile, @sveltejs/package@3.0.0-next.0 and @sveltejs/enhanced-img@1.0.0-next.0 also require Node 22, with enhanced-img additionally mandating Vite 8 and vite-plugin-svelte 7.

For users not ready to jump to v3, the 2.x line continues to improve. @sveltejs/kit@2.63.0 adds explicit environment variable support, and @sveltejs/kit@2.63.1 fixes a Windows path issue in generated env.d.ts imports and switches query.live to SSE. The @sveltejs/kit@2.62.0 release from earlier in the week lets you pass SvelteKit config through the Vite plugin, preserves multiple Set-Cookie headers on 304 responses, and catches streaming errors in load functions on the client.

Svelte core: quiet stability

The Svelte compiler itself saw three patch releases. svelte@5.56.1 adds compile-time errors for duplicate declaration tags and fixes cross-referencing between declarators. svelte@5.56.2 improves tracking of effect end nodes for async sibling components and quiets a false-positive reactivity loss warning. svelte@5.56.3 ignores errors in destroyed effects and types BigInts in $state.snapshot() returns.

Nuxt security hotfixes

Both Nuxt v3 and v4 received urgent security releases on the same day. Nuxt v4.4.7 and Nuxt v3.21.7 fix a noSSR assignment ordering issue in Nitro that could affect payload extraction, and patch a Vite allowDirs filtering bug where directories with shared prefixes could be incorrectly excluded. Users on either version should upgrade promptly.

Next.js backports and Turbopack progress

Next.js spread fixes across three release channels. The v16.2.7 backport resolves a dev mode hydration failure from HTTP cache, router.query corruption with basePath and rewrites, server action forwarding loops with middleware rewrites, and FormData entry dropping — the latter also backported to v15.5.19. On canary, Turbopack work continues with effect eviction and memory management, and improved NFT tracing.