#Is Rust Eating JavaScript?

In 2021, Lee Robinson predicted that Rust would eat JavaScript. By 2026, the prediction has largely come true, but not in the way you might think. Rust is not replacing JavaScript in the browser. It is replacing the engine underneath the developer tooling.

#What it is

Rust is a systems programming language that compiles to native machine code, has no garbage collector, and uses an ownership model to check memory safety at compile time. It runs close to the speed of C++ while catching many bugs before the code ever executes. JavaScript remains the language of the web, the thing running in browsers and on servers. But the tools that compile, bundle, minify, lint, format, and process CSS for JavaScript projects are increasingly written in Rust.

The shift started with SWC, a Rust-based compiler that replaced Babel and Terser inside Next.js. Then Turbopack became the default bundler for Next.js 16, and Rolldown became the default bundler for Vite 8. Rspack, Oxc, Biome, and Lightning CSS continued the spread, covering bundling, parsing, linting, formatting, and CSS processing. The wave even crossed into Python tooling, with uv replacing pip and Ruff replacing Flake8, Black, and isort.

#Why it matters

• Rust has no garbage collector and gives developers tighter control over memory, which matters for performance-critical tooling.
• The ownership model allows safe parallelism across CPU cores and catches data races at compile time, so tools can be both fast and correct.
• JavaScript developers benefit from Rust-powered tooling without having to write Rust themselves. You upgrade your framework and your builds get faster, even if you never touch a .rs file.
• The Rust wave has spread beyond JavaScript into Python, and AI coding agents are accelerating it because Rust's strict compiler creates a tight feedback loop for automated code generation.

#How it works

The JavaScript toolchain had been optimized for years, but it hit diminishing returns. Babel, Terser, webpack, ESLint, and Prettier were all written in JavaScript, and as projects grew, compile, bundle, lint, and format times accumulated. Rust-based tools replace those stages with native binaries that run faster and use multiple cores effectively.

SWC was the opening move, handling compilation and minification for Next.js and reportedly delivering 3x faster Fast Refresh and 5x faster builds at the time. By 2026, Turbopack is the default bundler in Next.js 16, and Rolldown is the default in Vite 8. Rspack replaces webpack, Oxc and Biome handle parsing, linting, and formatting, and Lightning CSS processes CSS. Deno brings Rust-based formatters and linters into the runtime.

AI coding agents are a new catalyst. Rust's strict compiler catches errors clearly, which gives agents structured feedback to iterate against. Lee Robinson's article cites Bun's agent-assisted core rewrite from Zig to Rust as an example of this trend.

#Caveats

Rust has a steep learning curve and its plugin ecosystem is harder to work with than JavaScript's. Switching to Rust does not save a bad algorithm or a poor architecture. Benchmark numbers from individual tools do not represent every codebase, and language choice alone does not guarantee speed. The real-world performance of a tool depends on its design, caching, plugin compatibility, and how well it fits the project using it.

#Who it's for

This matters for any developer using modern JavaScript tooling, whether they know it or not. If you use Next.js 16 or Vite 8, you are already running Rust under the hood. For tooling authors, Rust is worth considering for performance-critical work, but it is not a magic wand. For everyone else, the takeaway is simpler: your builds are getting faster because the engine is changing, even if your code stays the same.

Rust is not replacing JavaScript. It is becoming the engine of developer tooling. JavaScript stays in the cockpit; Rust is under the hood.

Source: https://leerob.com/rust