Sherlock relies on the site's designers providing a unique URL for a registered username. To determine if a username is available, Sherlock queries that URL, and uses to response to understand if there is a claimed username already there.

Currently, the tool is capable of locating users on more than 300 social networks: Apple Developer, Arduino, Docker Hub, GitHub, GitLab, Facebook, BitCoinForum, CNET, IFTTT, Instagram, PlayStore PyPI, Scribd, Telegram, TikTok, Tinder etc.