ffuf is a high-performance web fuzzer written in Go that helps security professionals identify hidden web application resources through rapid HTTP request generation. It uses the FUZZ keyword to inject payloads from wordlists into URLs, headers, and POST data, enabling comprehensive testing of web applications.

Key capabilities include:

Flexible fuzzing with custom keywords and multiple concurrent wordlists
Smart filtering by HTTP status codes, response sizes, and timing patterns
Recursive discovery to automatically explore nested directories and endpoints
High-speed execution with configurable threading and rate limiting
Multiple output formats including JSON and HTML for integration with security tools like Burp Suite
Auto-calibration to reduce false positives and improve accuracy

Common use cases include directory discovery, virtual host enumeration, parameter fuzzing, and API endpoint testing. The tool supports external mutators for advanced payload generation and configuration files for consistent testing profiles. Whether conducting authorized penetration tests or bug bounty assessments, ffuf delivers the speed and flexibility needed for thorough web application reconnaissance.