SilentShield is an invisible CAPTCHA alternative that protects forms, logins and checkouts from bots without image puzzles. The check runs in the background and rates each visit as human, suspicious or bot, based on how the form is filled in. Only when the result is unclear does the visitor see a short arithmetic task. A checkbox or a compact badge can be shown instead of the invisible mode. The service is hosted: you add a script tag with an API key to your pages and verify each submission with a server-side REST request; a WordPress plugin handles both steps without code.
SilentShield is operated by Forge12 Interactive GmbH, based in Donaueschingen, Germany. According to the vendor, data is kept on servers in Germany, the service is hosted entirely in the EU, no cookies are set and IP addresses are stored only as a hash. No open-source or self-hosted variant is described. For European organisations, this is a service from a German provider with processing inside the EU.