[1] Some have also described it as a search engine of service banners, which is metadata that the server sends back to the client.

[4] It was launched in 2009 by computer programmer John Matherly, who, in 2003,[5] conceived the idea of searching devices linked to the Internet.

[7][8][9] The website began as Matherly's pet project, based on the fact that large numbers of devices and computer systems are connected to the Internet.

[6][10] In May 2013, CNN Money released an article detailing how Shodan can be used to find vulnerable systems on the Internet, including traffic light controls.

[13] In December 2015, various news outlets, including Ars Technica, reported that a security researcher used Shodan to identify accessible MongoDB databases on thousands of systems, including one hosted by Kromtech, the developer of the macOS security tool MacKeeper.