| HSTS | 44,894 | https://www.rfc-editor.org/rfc/rfc6797#section-6.1 |
| reCAPTCHA | 7,237 | https://www.google.com/recaptcha/ |
| Cloudflare Bot Management | 6,274 | https://www.cloudflare.com/en-gb/products/bot-management/ |
| Akamai Bot Manager | 2,402 | https://www.akamai.com/us/en/products/security/bot-manager.jsp |
| Imperva | 945 | https://www.imperva.com/ |
| hCaptcha | 401 | https://www.hcaptcha.com |
| DDoS-Guard | 398 | https://ddos-guard.net |
| Forter | 117 | https://www.forter.com |
| DataDome | 103 | https://datadome.co |
| GeeTest | 58 | https://www.geetest.com |
| PerimeterX | 56 | https://www.perimeterx.com |
| Cloudflare Turnstile | 43 | https://www.cloudflare.com/products/turnstile |
| Solve Media | 26 | https://solvemedia.com |
| Kasada | 24 | https://www.kasada.io |
| Altcha | 17 | https://altcha.org |
| Confiant | 15 | https://www.confiant.com |
| Blue Triangle | 15 | https://bluetriangle.com |
| MTCaptcha | 15 | https://www.mtcaptcha.com |
| Very Good Security | 13 | https://www.verygoodsecurity.com |
| Yandex SmartCaptcha | 9 | https://cloud.yandex.com/en/services/smartcaptcha |