ESLint and Biome are both linters: tools that statically analyze JavaScript to find bugs and style problems. ESLint has a large plugin ecosystem. Biome ships one tool with many built-in rules across several languages. Neither replaces a security scanner, so pick on fit and add security checks separately.
What does ESLint do?
ESLint's documentation calls it a configurable JavaScript linter that helps find and fix problems, from potential runtime bugs to best practices to styling. Rules are its core building block. A rule checks that code meets an expectation and says what to do if it does not. It includes hundreds of built-in rules, and you can write custom rules or use rules from plugins, which are npm modules that can contain rules, configurations, processors and languages. Some rules provide fixes that can be applied automatically.
Its strength is the ecosystem. Frameworks and teams publish rule sets, and you can write a rule for a pattern unique to your code base.
What does Biome do?
Biome's linter statically analyzes code to find and fix common errors. Its documentation says it supports multiple languages and provides 568 rules, and some rules are language-agnostic, working across more than one language, for example in both JavaScript and CSS. Rule names follow a convention: those starting with use enforce or suggest something, and those starting with no deny something.
It distinguishes safe fixes from unsafe fixes. Safe fixes can be applied automatically on save. Unsafe fixes may change the semantics of your program, so they need review. That distinction is worth borrowing whatever tool you pick.
How do you choose?
Compare on the things that matter to your team.
Rules you need. List the rules you rely on today. Check whether the other tool has an equivalent. If you depend on a specific plugin, that may decide it.
Ecosystem and editor support. ESLint has a long history and broad framework coverage. Biome offers one dependency and one configuration to learn. Check your editor and CI setup for each.
Migration cost. Moving means translating configuration and accepting differences in behavior. Run both on a branch and compare output before switching.
Performance. Both can be fast enough for most projects. Measure on your own repository with your own rules before deciding, since claims vary by setup.
Maintenance. Look at release cadence, how issues are handled and how breaking changes are announced.
Is a linter a security tool?
Not by itself. OWASP describes source code analysis tools, also called static application security testing or SAST, as tools that analyze code to find security flaws. It lists strengths, such as scaling well and finding known patterns like SQL injection, and weaknesses: they have difficulty with authentication problems, access control issues and insecure use of cryptography, can produce many false positives, and often cannot find configuration issues because those are not in the code.
A general linter can catch some risky patterns, such as use of dynamic code evaluation, but it does not model data flow from user input to a dangerous call the way dedicated SAST does. Treat lint rules as the first, cheap layer.
A constructed example
A team of ten has an ESLint setup with four plugins, written two years ago. They try Biome on a branch. It covers most of the rules they use, and its output is quick to read, but two plugin rules for their UI framework have no equivalent. They keep ESLint for that package and use Biome elsewhere, then document why. Separately, they add a dependency check and a SAST step to CI, since neither linter looks at third-party packages.
How to check or apply this
- List the lint rules and plugins you depend on.
- Run the alternative on a branch and diff the findings.
- Decide per package, not per company. Mixed setups are acceptable if documented.
- Apply safe fixes automatically and review unsafe ones.
- Run the linter in CI so it blocks merges on errors.
- Add dependency scanning and SAST as separate steps for security coverage.
- Revisit the choice when your framework or toolchain changes.
Safeguard's SBOM and dependency scanning covers the third-party package side that linters do not see. It is complementary to linting and SAST, not a substitute for either.
Quick check
Can Biome and ESLint run together?
Yes, though overlapping rules can conflict. Many teams split by package or by rule category and document the split.
Will a linter find SQL injection?
Only simple patterns, if a rule exists. Dedicated SAST tools trace data flow and are better suited, though OWASP notes they also have false positives and gaps.
Sources
Last reviewed: 18 October 2026.
