Why is Biome faster than its alternatives?

#Why is Biome faster?

#1. Biome is written in Rust

The main reason is Rust.

• Rust compiles to native machine code
• There is no garbage collector
• High optimization of computations
• Excellent multithreading support

Compared to JavaScript (in which ESLint and Prettier are written), Rust works:

• faster on CPU-intensive tasks
• more stably when processing large amounts of code
• more safely in terms of memory leaks

Linting and formatting are exactly CPU-heavy tasks, so Rust is an ideal choice.

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#2. A single high-performance parser

Biome uses one shared parser (for JS, TS, JSX, JSON, and so on).

ESLint usually works like this:

• connects an external parser (@typescript-eslint/parser)
• this parser converts the code into an AST
• then ESLint plugins read the AST
• then ESLint rules traverse the AST again
• then a separate tool, Prettier, re-parses the file
• and traverses the AST again for formatting

So the code is parsed several times by different tools.

#In Biome, it is the opposite:

• one universal parser
• one AST
• one pass
• minimal extra layers

One pass over the tree instead of the 2-4 passes in ESLint/Prettier.

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#3. No dynamic plugin loading

ESLint is slow because:

• it requires dozens of plugins
• each plugin is a separate JS function
• all of them are loaded and interpreted at startup

Biome:

• has almost everything built in
• has no heavy plugin system (at this point)
• rules are optimized at the compilation level

Less JavaScript code → less IO → less interpretation.

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#4. Optimized AST traversal architecture

ESLint:

• each rule walks the AST independently
• rules often repeat each other's work
• enabling 50+ rules creates 50+ traversals

Biome:

• performs a centralized, optimized tree traversal
• uses static checks at the compilation stage
• minimizes repeated traversals

One traversal instead of many is a huge time saving.

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#5. No Node.js limitations

Node.js:

• is slow on heavy computations
• has single-threading limitations
• suffers from the high cost of GC operations

Biome:

• uses Rust's capabilities for parallelism
• works with memory directly
• does not depend on V8 and its limitations

Rust is better suited for intensive parsing and analysis tasks.

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#6. Minimal configuration = minimal work

ESLint:

• even a basic configuration uses:
  • a parser
  • an Airbnb/Next/React config
  • linters for imports
  • linters for TS
  • integration with Prettier

All of this is loaded and analyzed before startup.

Biome:

• one config
• no third-party extensions besides core rules
• optimization at the binary level

Faster startup, less code, fewer layers.

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#7. The formatter is built in, not a separate process

Prettier is a separate tool. ESLint is a separate tool. They do not optimize each other's work in any way.

Biome:

• the formatter is part of a single engine
• there is no extra work from re-parsing
• there are no conflicts between the formatter and the linter

2 tools → 1 engine → 1 pass → faster.