Contributing to AFL++

Guidelines for contributing code and documentation to AFL++

Submitting Pull Requests

All contributions (pull requests) must be made against the dev branch.

Code Formatting

Each modified source file, before merging, must be formatted:

make code-format

This works for files already present in the project. If you added a file in a new directory:

./.custom-format.py -i file-that-you-have-created.c

Coding Style

Please follow the AFL style:

• No camel case at all
• Use AFL’s macros wherever possible (e.g., WARNF, FATAL, MAP_SIZE, etc.)
• Keep code readable and well-commented

Cross-Platform Compatibility

Remember that AFL++ has to build and run on many platforms:

• Generalize your Makefiles/GNUmakefile
• Make patches to pre-existing Makefiles as generic as possible
• Test on multiple platforms when possible

Contributing to Documentation

We welcome contributions to our docs!

Documentation Structure

Before creating a new file, check if your content matches an existing file in:

• docs/ (most documentation content)
• frida_mode/
• instrumentation/
• nyx_mode/
• qemu_mode/
• unicorn_mode/

Documentation Guidelines

File Naming

• ✅ Use Markdown files: fuzzing_gui_program.md
• ❌ Don’t use other formats: fuzzing_gui_program.txt
• ✅ Use underscores: fuzzing_network_service.md
• ❌ Don’t use hyphens: fuzzing-network-service.md

Formatting

• Use a maximum of 80 characters per line (easier to read in console)
• Make all pull requests against dev branch

Writing Best Practices

• Use clear and simple language
• Structure content with headings and paragraphs
• Use bulleted lists for similar content (easy to scan)
• Use numbered lists for procedures or prioritizing
• Link to related content (prerequisites, in-depth discussions)

Getting Help

If you have questions about contributing:

• Check existing GitHub Discussions
• Review existing pull requests for examples
• Ask in the AFL++ community channels

Code of Conduct

Be respectful and constructive in all interactions with the AFL++ community.

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Thank you for contributing to AFL++! Your contributions help make fuzzing more accessible and effective for everyone.