Smap

Smap is a passive port scanner designed as a drop-in alternative to Nmap while using Shodan.io data. It accepts many familiar Nmap-style command-line arguments and can produce Nmap-like output formats, which makes it easier to integrate into existing workflows. Because it relies on Shodan’s free API, it can scan quickly without directly contacting targets in its default mode. The project emphasizes speed, with support for scanning large numbers of hosts per second. Smap can provide service and version fingerprinting, vulnerability detection, and results in formats such as XML, greppable, normal, JSON, and custom output. It is useful for authorized reconnaissance where fast external visibility matters, while users should remember that passive results may be delayed or incomplete compared with active scanning.