Next.js Daily: SWC Configuration and Performance Updates

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Good morning. This is Next.js Daily for Friday, April 4th, 2026.

The development team merged 18 pull requests yesterday with significant updates to SWC configuration and Turbopack performance.

banchichen merged a major feature adding experimental.swcEnvOptions for SWC preset-env configuration. This exposes polyfill injection capabilities including core-js support, filling a gap left when Next.js migrated from Babel to SWC. Users can now configure automatic polyfills without importing core-js globally.

sokra merged custom Future types to replace async resolve functions in turbo-tasks, reducing binary size by 428 kilobytes and improving performance through hand-written Future implementations.

lukesandberg merged zero-copy qfilter deserialization for Turbopack, switching from heap-allocated filters to memory-mapped FilterRef types. This reduces memory usage by approximately 40 megabytes on large projects like vercel-site.

Will Binns-Smith updated the Rust toolchain to nightly-2026-04-02, cleaning up 22 clippy violations across the codebase.

sokra also added a new MCP get_compilation_issues tool that returns all compilation issues from all routes in a single call, improving developer tooling integration.

Additional notable merges include bgw's fix for restarting the dev server when the .next directory is deleted, and ztanner's improvement to ISR revalidation error reporting in App Router pages.

The team also reverted session dependent tasks changes due to out-of-memory issues in applications with persistent caches.

What's next: The new SWC configuration options provide a foundation for better polyfill management, while the Turbopack memory optimizations should improve performance on large codebases. The team continues refining the development experience with better error handling and tooling integration.

That's Next.js Daily for April 4th. We'll be back Monday with more updates.