skipfish is described as 'A fully automated, active web application security reconnaissance tool. Key features: High speed: pure C code, highly optimized HTTP handling, minimal CPU footprint - easily achieving 2000 requests per second with responsive targets' and is a vulnerability scanner in the os & utilities category. There are more than 25 alternatives to skipfish for a variety of platforms, including Windows, Linux, Web-based, Mac and Android apps. The best skipfish alternative is Nmap, which is both free and Open Source. Other great apps like skipfish are Zenmap, Shodan, Zed Attack Proxy (ZAP) and Nessus.