--- title: Biome v2.5—500 Lint Rules, Plugin Code Fix, and... description: Biome v2.5 has been released, surpassing 500 lint rules with 73 nursery rules promoted to stable. Key highlights include two new cross-language lint rules... canonical: https://daily.dev/posts/biome-v2-5-500-lint-rules-plugin-code-fix-and-cross-file-linting-akdrer8h7 twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Biome v2.5—500 Lint Rules, Plugin Code Fix, and Cross-File Linting | daily.dev og:description: Biome v2.5 has been released, surpassing 500 lint rules with 73 nursery rules promoted to stable. Key highlights include two new cross-language lint rules... og:url: https://daily.dev/posts/biome-v2-5-500-lint-rules-plugin-code-fix-and-cross-file-linting-akdrer8h7 og:image: https://api.daily.dev/og/posts/Akdrer8h7.png og:image:alt: Biome v2.5—500 Lint Rules, Plugin Code Fix, and Cross-File Linting og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # Biome v2.5—500 Lint Rules, Plugin Code Fix, and Cross-File Linting **[Biome Blog](https://daily.dev/sources/biome)** · 10 min read · 50 upvotes · 2 comments ## Summary Biome v2.5 has been released, surpassing 500 lint rules with 73 nursery rules promoted to stable. Key highlights include two new cross-language lint rules (noUndeclaredClasses and noUnusedClasses) that leverage the module graph to detect CSS class mismatches across HTML/JSX/CSS files, a noRestrictedDependencies rule based on the e18e initiative, and GritQL plugin improvements including path-specific plugin application and code fix support. The release also adds a new delimiterSpacing formatter option for accessibility, a --watch mode for lint/format/check commands, go-to definition support in the language server, a linter preset option replacing the deprecated recommended flag, a biome upgrade command, a concise reporter for AI coding agents, and ~13% performance improvements. SVG file support, pnpm catalog resolution, and new sorting assist actions for package.json and other file types are also included. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Questions this post answers ### What new lint rules does Biome 2.5 add for CSS class usage? Biome 2.5 introduces two nursery rules, noUnusedClasses and noUndeclaredClasses, that use Biome's module graph for cross-file analysis. noUnusedClasses flags CSS classes not referenced in any HTML-ish or JSX files, while noUndeclaredClasses flags class or className attributes not defined in any CSS file or style tag, and it also detects the :global() pseudo-selector. _Track new Biome linting capabilities like these on daily.dev before adopting them in a project._ ### Can Biome plugins apply automatic code fixes in version 2.5? Yes, as of Biome 2.5, GritQL plugins can declare a code fix using the => symbol combined with the register_diagnostic function's new fix_kind option. Fixes default to "unsafe" and only apply with --write --unsafe, but can be marked "safe" to apply with a plain --write. _Developers evaluating linter plugin capabilities can follow releases like this one on daily.dev._ ### How much faster is Biome's lint and check command in version 2.5? Biome's lint and check commands are about 13% faster in version 2.5 compared to the prior release. This release also adds SVG file linting and formatting support alongside the performance improvement. _Keep tabs on tooling performance gains like Biome's on daily.dev when comparing linters._ ## Community discussion Top comments from developers on daily.dev. **@yaireo** · 0 upvotes > I ❤️Biome **@brunodebrito** · 0 upvotes >  ## Similar posts on daily.dev - [Pre-commit Hooks 15× Faster \(Biome vs ESLint Case Study\) : fireup.pro](https://daily.dev/posts/pre-commit-hooks-15-faster-biome-vs-eslint-case-study-fireup-pro-fsuvxtmdx) · FireUp · 1 upvotes · 0 comments - [ESLint v10: Flat Config Completion and JSX Tracking](https://daily.dev/posts/eslint-v10-flat-config-completion-and-jsx-tracking-muqydccwu) · InfoQ · 0 upvotes · 0 comments - [Prettier 3.7: Improved formatting consistency and new plugin features\! · Prettier](https://daily.dev/posts/prettier-3-7-improved-formatting-consistency-and-new-plugin-features-prettier-dirzsvngi) · Prettier · 90 upvotes · 0 comments - [Ultracite: Opinionated, zero-config code linter and formatter](https://daily.dev/posts/ultracite-opinionated-zero-config-code-linter-and-formatter-ywsplmmxb) · Product Hunt · 24 upvotes · 1 comments --- Tags: [#javascript](https://daily.dev/tags/javascript), [#rust](https://daily.dev/tags/rust) [View this post on daily.dev](https://daily.dev/posts/biome-v2-5-500-lint-rules-plugin-code-fix-and-cross-file-linting-akdrer8h7) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"Biome v2.5—500 Lint Rules, Plugin Code Fix, and Cross-File Linting","url":"https://daily.dev/posts/biome-v2-5-500-lint-rules-plugin-code-fix-and-cross-file-linting-akdrer8h7","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/biome-v2-5-500-lint-rules-plugin-code-fix-and-cross-file-linting-akdrer8h7"},"datePublished":"2026-07-26T07:48:45.884Z","dateModified":"2026-09-14T08:03:40.762Z","description":"Biome v2.5 has been released, surpassing 500 lint rules with 73 nursery rules promoted to stable. 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