Context
Finding problematic code (lint) and standardizing its formatting (format) are two problems historically solved by separate tools in the JavaScript ecosystem — and that's exactly where Biome and the ESLint + Prettier duo disagree about how many moving pieces that solution should have. ESLint was born as a lint tool, and formatting was never part of its original scope: that role belongs to Prettier, a separate project, with its own configuration file, its own version, and its own release cycle. Running the two together has historically required an extra layer of configuration — something like eslint-config-prettier — just to turn off the ESLint style rules that would conflict with what Prettier already decides on its own.
Biome was born later, as a direct response to that fragmentation: a single binary, written in Rust, that does lint and format with the same parser and the same configuration, without depending on two projects agreeing on who decides what. The facts table above reflects only the eslint package — Prettier is installed, versioned, and has its own license and its own download count, which don't show up in these numbers because it is, in fact, a separate package from ESLint.
When to choose Biome
Biome pays off when the team wants to consolidate lint and format into a single tool, with minimal configuration and processing speed that comes from being compiled instead of interpreted:
// biome.json
{
"linter": { "enabled": true },
"formatter": { "enabled": true, "indentStyle": "space" }
}
A single file covers both responsibilities, and because the same engine does lint and format, the entire category of "the formatter undid what the linter asked for" bug — which shows up when two independent tools compete over the same styling responsibility — doesn't exist. Because the parser is shared between lint and format, Biome also manages to run both steps in a single pass over the file's syntax tree, instead of two tools reading and re-analyzing the same code independently — part of where the speed gain in large codebases comes from. The trade-off is ecosystem maturity: Biome's lint rule set, while it grows with every release, is still smaller than the years-long collection of framework-, library-, or team-convention-specific plugins that exists for ESLint — so teams with strong dependencies on very specific rules may not find a ready equivalent in Biome.
When to choose ESLint + Prettier
ESLint + Prettier pays off when the project depends on specific plugins — for a framework, a library, or an accessibility convention — that only exist in the ESLint ecosystem, built over many years by a much larger community:
// eslint.config.js
export default [
{ plugins: { "jsx-a11y": jsxA11y }, rules: { "jsx-a11y/alt-text": "error" } },
];
This accessibility plugin is just one example among thousands published for ESLint — covering practically any framework, code standard, or business rule a team wants to enforce automatically. Prettier, for its part, solves formatting in isolation and is widely adopted, with its own already-mature configuration and editor integration — but precisely because it's a separate project, it doesn't share a parser or syntax tree with ESLint, so the two tools need explicit configuration (like a preset that disables ESLint's style rules) to avoid fighting over the same line of code. The trade-off of keeping both is having two tools to configure, update, and keep compatible with each other — which Biome solves by consolidating into a single piece, at the cost of a rule ecosystem still under construction.
Verdict
This isn't a "whoever's faster wins" contest: Biome wins on speed and configuration simplicity almost every time, but that only matters if the rule set it already covers is enough for your project. For teams that mostly use generic JS/TS lint and format, without a large stack of framework-specific plugins, Biome consolidates two tools into one with no perceptible loss. For teams that already depend on a niche plugin from the ESLint ecosystem — whether for accessibility, a specific framework, or an internal convention published as a package — switching tools means first confirming whether that specific plugin has an equivalent in Biome, not the other way around.