Build Tools & Bundlers

The bundler space went through a Rust-rewrite era. By 2026 the picture is roughly:

Dev / app bundler

• ★ Vite 7 — the default for SPAs, libraries, and many meta-frameworks (SvelteKit, Astro, Solid Start, TanStack Start, Remix/RR7).
• ★ Turbopack — Next.js's bundler; default for next dev and next build in Next 16.
• Rspack — Rust port of webpack with high webpack compatibility. Used by ByteDance internally; growing OSS adoption.
• Rolldown — Rust rewrite of Rollup (from the Vite/Vue team); will become Vite's underlying bundler.

Transformers

• SWC — Rust transpiler used by Next.js, Vercel.
• esbuild — Go-based; foundation for Vite's dev server pre-bundling.
• Babel — still ubiquitous for plugin-heavy use cases (custom JSX transforms, decorators, complex syntax extensions).
• OXC — fastest JS toolchain in Rust (parser, transformer, resolver, linter — oxlint).

Library bundling

• tsup — esbuild-powered library bundler; the default for new TS libraries.
• unbuild — lightweight, used by Nuxt / Nitro projects.
• Vite's library mode — for SPAs/components.
• Rolldown (when stable) — the future for libraries that pick Rollup-style ergonomics.

Runtime / dev servers

• Bun — replaces Node + npm + bundler + test runner; production-ready for many uses.
• Deno 2 — Node-compatible, npm-compatible, web standard APIs first.

Other

• Lightning CSS — CSS bundler/transformer (Rust); inside Tailwind v4 and others.
• CSS Modules + PostCSS — still the default CSS pipeline.

Pick this if…

• Default SPA / library: Vite.
• Next.js: Turbopack (no choice; it's the default).
• Library author: tsup (today), Rolldown (soon).
• Massive existing webpack config: Rspack (drop-in), or stick with webpack 5.
• Want one tool that does it all: Bun.