clang-tidy

Free plan Linux

What clang-tidy is

clang-tidy is a free, open-source Clang-based linter for C++ that diagnoses and can help fix typical programming errors, style violations, interface misuse and bugs detectable by static analysis. Its checks cover bug-prone code, CERT guidelines, the C++ Core Guidelines, performance, portability and readability; it can also run Clang Static Analyzer checks. Select checks with the `-checks=` option, which accepts comma-separated positive and negative globs. The `-fix` flag applies corrections for findings when supported by the relevant checks. Configuration can be stored in `.clang-tidy` files, including check choices, check-specific options and custom checks. clang-tidy uses LibTooling and works with a compilation database such as `compile_commands.json`; compiler options can also be provided on the command line. The included `run-clang-tidy.py` script analyzes files concurrently. `clang-tidy-diff.py` filters reported diagnostics to changed lines, but still analyzes each whole file. Developers can write custom checks using preprocessor callbacks or AST matchers, with fix-it hints attached to diagnostics. Listed integrations include clangd and several IDEs and editors. CUDA analysis is supported with a specified toolkit path.

Who it suits

clang-tidy suits C++ developers who want configurable linting and static-analysis checks in a project workflow. Its custom-check interface and IDE integrations may also suit teams with tailored coding rules.

What it does well

Free and open source.
Supports automatic fixes when checks allow them.
Custom checks can use AST matchers.
Includes concurrent analysis tooling.

What to know first

Changed-line filtering still analyzes the whole file.
Some builds omit clang-analyzer and mpi checks.
A compilation database is needed for that workflow.

Limits

The tool is free with no paid plans or usage limits stated. `clang-tidy-diff.py` filters displayed diagnostics to changed lines but still analyzes entire files, and `clang-analyzer-*` or `mpi-*` checks are unavailable when built with `CLANG_TIDY_ENABLE_STATIC_ANALYZER=NO`.

Plans

Plan	Billed and limits	Price
clang-tidy	No paid plans or usage limits stated	Free

As clang.llvm.org lists them, read 11 Oct 2026. The maker's own page has the final word.

Getting started

Install or build clang-tidy for Linux
Prepare a compilation database such as `compile_commands.json`
Select checks with the `-checks=` option
Add project settings to a `.clang-tidy` file if needed
Run clang-tidy directly or use `run-clang-tidy.py` for concurrent analysis
Use `-fix` when supported corrections are appropriate

Verdict

clang-tidy offers configurable C++ checks, supported automatic fixes and custom-rule options without a listed paid plan. Note that changed-line filtering does not reduce the whole-file analysis, and some builds exclude specific check groups.

Questions

What does clang-tidy cost?

clang-tidy is free and open source. Its listed plan is free.

Which language does it support?

The listing reports support for 3 languages and describes clang-tidy as a C++ linter.

Can clang-tidy fix findings automatically?

Yes. The `-fix` flag applies fixes when the corresponding checks support them.

Does it support IDEs and CI?

Yes. Integrations include clangd, CLion, KDevelop, Qt Creator, Visual Studio tools, Vim, and Emacs Flycheck, and it supports CI workflows.

Can teams write custom checks?

Yes. Custom checks can use preprocessor callbacks or AST matchers, with fix-it hints attached to diagnostics.

Who makes clang-tidy?

It is an LLVM project tool; LLVM describes itself as a collection of modular, reusable compiler and toolchain technologies.

Facts from clang-tidy's own pages

Automatic fixes: The -fix option applies suggested fixes when supported by the corresponding checks. · clang.llvm.org, 11 Oct 2026
Build integration: clang-tidy can use a compile command database, which CMake can generate with CMAKE_EXPORT_COMPILE_COMMANDS=ON. · clang.llvm.org, 11 Oct 2026
Build options: If built with `CLANG_TIDY_ENABLE_STATIC_ANALYZER=NO`, clang-tidy does not include support for `clang-analyzer-*` or `mpi-*` checks. · clang.llvm.org, 11 Oct 2026
Changed-line analysis: `clang-tidy-diff.py` filters reported diagnostics to changed lines, but still analyzes the entire file and does not improve analysis performance. · clang.llvm.org, 11 Oct 2026
Check categories: Its check groups include bug-prone code, CERT guidelines, C++ Core Guidelines, performance, portability, and readability checks. · clang.llvm.org, 11 Oct 2026
Checks: It provides its own checks and can also run Clang Static Analyzer checks. · clang.llvm.org, 11 Oct 2026
Check selection: Checks can be selected with the `-checks=` option, which accepts comma-separated positive and negative globs. · clang.llvm.org, 11 Oct 2026
clangd support: The Clang team recommends clangd, which integrates clang-tidy and is available in major editors through plugins including Vim, Emacs, Visual Studio Code, and Sublime Text. · clang.llvm.org, 11 Oct 2026
Configuration: Checks can be selected with comma-separated positive and negative globs, and configuration can be read from a .clang-tidy file. · clang.llvm.org, 11 Oct 2026
CUDA support: clang-tidy supports CUDA source analysis, with the CUDA toolkit path specified using --cuda-path for correct header resolution. · clang.llvm.org, 11 Oct 2026
Custom checks: The tool provides an interface for writing custom checks, which can use preprocessor callbacks or AST matchers and attach fix-it hints to diagnostics. · clang.llvm.org, 11 Oct 2026
Diff workflow: clang-tidy-diff.py filters diagnostics to changed lines, but still analyzes the entire file and may miss issues reported outside those lines. · clang.llvm.org, 11 Oct 2026
Extensible checks: The tool is modular and provides a framework for writing new checks. · clang.llvm.org, 11 Oct 2026
IDE/editor integrations: The documentation links to a Clang-tidy IDE/Editor Integrations page. · clang.llvm.org, 11 Oct 2026
IDE integrations: The documentation lists integrations including clangd, CLion, KDevelop, Qt Creator, Visual Studio tools, Vim plugins, and Emacs Flycheck. · clang.llvm.org, 11 Oct 2026
License: The LLVM project states that its code is licensed under the Apache 2.0 License with LLVM exceptions. · llvm.org, 11 Oct 2026
Maker: LLVM describes itself as a collection of modular and reusable compiler and toolchain technologies, and identifies clang-tidy as an LLVM project tool. · llvm.org, 11 Oct 2026
Parallel analysis: The included `run-clang-tidy.py` script runs analysis over files in a compilation database concurrently. · clang.llvm.org, 11 Oct 2026
Parallel runs: The included run-clang-tidy.py script runs analysis concurrently across files in a compilation database or specified path. · clang.llvm.org, 11 Oct 2026
Project setup: clang-tidy is based on LibTooling and works with a compilation database such as `compile_commands.json`; compiler options can also be supplied on the command line. · clang.llvm.org, 11 Oct 2026
Purpose: clang-tidy is a Clang-based C++ linter for diagnosing and fixing typical programming errors, including style violations, interface misuse, and bugs detectable by static analysis. · clang.llvm.org, 11 Oct 2026
Security checks: The documented check groups include CERT secure coding checks and Clang Static Analyzer checks, among other categories. · clang.llvm.org, 11 Oct 2026
Static analysis: clang-tidy includes its own checks and can also run Clang Static Analyzer checks. · clang.llvm.org, 11 Oct 2026

Where clang-tidy stands on Freedom251

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