Smap
a drop-in replacement for Nmap powered by shodan.io
...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.