Biome

Biome is a toolchain that replaces a formatter and a linter with a single Rust binary. It formats JavaScript, TypeScript, JSX, JSON, and CSS, and it lints the same file set, so a project configures one tool and runs one command instead of coordinating several. The project began as a fork of Rome Tools after that project was discontinued, and it inherited the goal of unifying the tools that a JavaScript project normally assembles from separate packages. Because the implementation is compiled, checks run without the startup cost that accumulates when several Node-based tools each parse the project separately. Diagnostics are designed to be actionable: a lint error points at the rule, explains the problem in prose, and in many cases offers a safe fix that can be applied automatically. The main limitation is breadth. Biome's rule set does not yet cover everything a mature ESLint configuration with type-aware rules can express, so projects with heavy custom lint requirements sometimes run both.