This product is listed as “Self-hosted & Open Source”, which is why it does not necessarily have to be European.
mCaptcha is an open-source captcha service for self-hosting. It uses proof-of-work and is compatible with reCAPTCHA and hCaptcha. mCaptcha is licensed under the AGPL license.
Trustcaptcha is a captcha service from Germany. They protect your website from bot and spam attacks while protecting the data of your customers without annoying them with puzzles, or other tasks. A free demo of this can be found on their website.
Friendly Captcha is a captcha service from Germany that helps users protect websites from bots. It works in such a way that no interaction with the captcha service is necessary except for clicking on a checkbox. Thus, the user does not have to select images or decipher bent letters.
