Next.js 15.5: Goodbye ESLint and Prettier, Hello Biome

The frontend ecosystem is changing fast, with new tools popping up that promise better speed, simplicity, and developer experience. One of the biggest shifts came from Next.js: starting with version 15.5 (August 2025), the framework officially moved away from the ESLint + Prettier combo in favor of Biome.

A Bit of Backstory

The release of ESLint v9 (April 2024) stirred up quite a bit of frustration in the community—many developers were forced to rewrite their configs due to breaking changes, and migration wasn’t exactly smooth. Around the same time, Biome started gaining traction—marketed as a fast, all-in-one alternative to both ESLint and Prettier.

Since then, its popularity has only grown. Now, with Next.js and Vercel backing Biome, it looks more and more like this tool could become the new standard.

Of course, ESLint still has its strengths. Its ecosystem of plugins and fine-grained configuration is unmatched. But Biome’s speed advantage is undeniable—faster tooling directly translates into smoother developer experience and quicker CI/CD pipelines.

What Changed in Next.js 15.5?

The familiar next lint command — which previously ran ESLint (and relied on Prettier for formatting) — is now deprecated. Instead, developers must choose explicitly:

• Biome — a blazing-fast tool combining linting and formatting.
• ESLint — still supported, but now requires explicit setup via eslint.config.mjs.

So next lint is no longer a black box. You pick your tool.

What Does the New Setup Look Like?

Biome

{
  "scripts": {
    "lint": "biome check",
    "format": "biome format --write"
  }
}

ESLint

{
  "scripts": {
    "lint": "eslint",
    "lint:fix": "eslint --fix"
  }
}

Next.js includes a codemod to help migrate configs and dependencies to either option—no manual work needed.

Biome vs ESLint + Prettier: Benchmarked Comparison

Feature	ESLint + Prettier	Biome (measured)
Formatting speed	Standard (JS-based, slower)	Up to 25× faster than Prettier (OpenReplay, AppSignal)
Linting speed	Standard (JS-based, slower)	Around 15× faster than ESLint (OpenReplay, AppSignal)
Developer feedback speeds	N/A	~ 15× faster linting in benchmarks (Reddit)
Setup complexity	Multiple tools & configs	Single tool, unified config
Customization	Very high (many plugins)	Growing, but limited ecosystem
CI/CD impact	Slower build times	Noticeably faster tooling

My Personal Take

I migrated one of my pet projects to Biome, and the experience has been excellent. The configuration is simpler, one command handles both lint and format, and I can feel the speed—especially on CI/CD where saving seconds scales up.

Bottom Line

The switch to Biome in Next.js 15.5 is more than just tooling—it signals a shift toward faster, leaner, and more unified development.

If you maintain existing projects, a Biome trial might surprise you. For new projects—Biome feels like the future.