nuclei is described as 'Nuclei is used to send requests across targets based on a template, leading to zero false positives and providing fast scanning on a large number of hosts. Nuclei offers scanning for a variety of protocols, including TCP, DNS, HTTP, SSL, File, Whois, Websocket, Headless etc' and is a vulnerability scanner in the security & privacy category. There are more than 25 alternatives to nuclei for a variety of platforms, including Windows, Web-based, Linux, Mac and SaaS apps. The best nuclei alternative is Burp Suite, which is free. Other great apps like nuclei are OpenVAS, Zed Attack Proxy (ZAP), Nessus and Lonkero.