| HSTS | 3,508,413 | https://www.rfc-editor.org/rfc/rfc6797#section-6.1 |
| reCAPTCHA | 688,900 | https://www.google.com/recaptcha/ |
| Cloudflare Bot Management | 687,784 | https://www.cloudflare.com/en-gb/products/bot-management/ |
| Akamai Bot Manager | 54,489 | https://www.akamai.com/us/en/products/security/bot-manager.jsp |
| hCaptcha | 31,720 | https://www.hcaptcha.com |
| DDoS-Guard | 26,642 | https://ddos-guard.net |
| Imperva | 24,106 | https://www.imperva.com/ |
| CleanTalk | 2,893 | https://cleantalk.org |
| Arkose Labs | 1,759 | https://www.arkoselabs.com |
| ClickCease | 1,509 | https://www.clickcease.com |
| Variti | 1,060 | https://variti.io |
| DataDome | 838 | https://datadome.co |
| Negate | 762 | https://negate.io |
| PerimeterX | 575 | https://www.perimeterx.com |
| Securiti | 561 | https://securiti.ai |
| GeeTest | 521 | https://www.geetest.com |
| AntiBot.Cloud | 386 | https://antibot.cloud |
| Yandex SmartCaptcha | 378 | https://cloud.yandex.com/en/services/smartcaptcha |
| Basic | 336 | https://tools.ietf.org/html/rfc7617 |
| NoFraud | 325 | https://www.nofraud.com |