Free and open first
Best Linters in 2026
Linters help check code against rules and catch issues during development. Compare languages supported and IDE support with CI support to see how each option fits your editing and automated-check workflows. Autofix, custom rules, and security rules offer further points of comparison, while free-plan availability and paid-from pricing can help you weigh cost. The entries include Biome, Cppcheck, and PMD. Consider the languages and checks your projects need, then compare the listed capabilities to find options that fit your workflow.
- 33 apps
- Research read 23 Sept 2026
- How the order is worked out
- 1
Cppcheck
Free plan Open source LinuxMacSelf-hosted+1Cppcheck offers core C and C++ analysis for free, with paid licensing adding standards checks and compliance reporting.
- 2
Flake8
Free plan Open source APILinuxMac+2Choose Flake8 for free, configurable Python checks from the command line, especially when plugins or version-control hooks fit your workflow.
- 3
JSHint
Free plan Open source APIExtensionLinux+4JSHint offers configurable checks and integrations across JavaScript development workflows. Its own limits mean developers should pair it with tests and code reviews.
- 4
actionlint
Free plan LinuxMacSelf-hosted+2actionlint covers workflow structure, expression semantics, reusable workflow interfaces, and selected security risks.
- 5
Biome
Free plan ExtensionLinuxMac+2Biome provides a free toolchain for formatting and linting web-project code, with editor and CI integration options.
- 6
Astral
Free plan LinuxMacWindowsAstral offers free, open-source Python tools for linting and package and project management. The separate pyx registry is closed to new signups, and support is directed to Discord.
- 7
Checkstyle
Free plan LinuxMacWindowsChoose Checkstyle if you need free, configurable checks to help Java code follow a coding standard across command line, build, IDE, or CI workflows.
- 8
cpplint
Free plan LinuxMacWindowsChoose cpplint if you need a free command-line style checker for C and C++ and want to run it in pre-commit or CI workflows.
- 9
golangci-lint
Free plan LinuxMacSelf-hosted+1golangci-lint brings parallel linting, configuration, and integrations to Go workflows at no listed cost.
- 10
Hadolint
Free plan LinuxMacWeb+1Hadolint offers configurable Dockerfile checks and integration options across development workflows. Its focus is narrow by design: it checks Dockerfiles and Bash code within RUN instructions.
- 11
detekt
Free plan LinuxMacWindowsdetekt offers configurable Kotlin analysis and several report formats, with options for extending its rules. Check the Gradle requirement if you plan to use its plugin.
- 12
ESLint
Free plan APIExtensionSelf-hostedESLint offers configurable JavaScript analysis with automatic fixes and broad documented integrations. Confirm the Node.js requirement and version-support window fit your environment.
- 13
Luacheck
Free plan LinuxMacSelf-hosted+1Luacheck provides configurable checks for Lua code, with several output formats and documented CI and editor integrations.
- 14
clang-tidy
Free plan Linuxclang-tidy offers configurable C++ checks, supported automatic fixes and custom-rule options without a listed paid plan.
- 15
HLint
Free plan LinuxMacWindowsHLint offers configurable Haskell suggestions, reports, and integrations across major desktop platforms.
- 16
PHPMD
Free plan LinuxMacSelf-hosted+1Choose PHPMD for free PHP source analysis with predefined and custom rules, plus CI reporting options. It supports several operating systems and self-hosted use.
- 17
PMD
Free plan LinuxMacSelf-hosted+1PMD combines broad language coverage, custom rules, and bundled duplicate detection without a listed price. Check language-specific rule coverage and version support before adopting it.
- 18
Clippy
Free plan LinuxMacWindowsClippy offers broad, configurable lint coverage for Rust projects, including workspace and CI workflows. Developers should review automated suggestions and enable restrictive categories selectively.
- 19
Oxc
Free plan LinuxMacWindowsOxc brings multiple JavaScript development tools into one free collection, with broad lint rules and formatter support.
- 20
Ruff
Free plan LinuxMacSelf-hosted+2Ruff combines Python linting, formatting and fixes, with integrations for common editors and CI workflows.
- 21
pycodestyle
Free plan LinuxMacWindowsChoose pycodestyle for free, configurable checks of selected PEP 8 conventions, especially when editor navigation or plugin extensions matter.
- 22
ShellCheck
Free plan ExtensionLinuxMac+2ShellCheck offers several ways to review shell scripts, from a browser paste to editor and CI integrations.
- 23
SQLFluff
Free plan APILinuxMac+2SQLFluff offers broad dialect support, configurable rules, and automated fixes without executing SQL itself.
- 24
Stylelint
Free plan APILinuxMac+1Stylelint provides flexible CSS linting through its CLI, Node.js API and PostCSS integration.
- 25
Credo
Free planCredo combines Elixir code checks with explanations intended to help users understand and configure findings.
#1Places #1, #2, #3, #4, #5 on this list can be bought by the makers of the software on it. See the price
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