| HSTS | 1,835,879 | https://www.rfc-editor.org/rfc/rfc6797#section-6.1 |
| reCAPTCHA | 379,665 | https://www.google.com/recaptcha/ |
| Cloudflare Bot Management | 363,700 | https://www.cloudflare.com/en-gb/products/bot-management/ |
| Akamai Bot Manager | 30,739 | https://www.akamai.com/us/en/products/security/bot-manager.jsp |
| hCaptcha | 17,429 | https://www.hcaptcha.com |
| Imperva | 15,129 | https://www.imperva.com/ |
| DDoS-Guard | 13,013 | https://ddos-guard.net |
| CleanTalk | 1,493 | https://cleantalk.org |
| Arkose Labs | 991 | https://www.arkoselabs.com |
| ClickCease | 831 | https://www.clickcease.com |
| DataDome | 528 | https://datadome.co |
| Variti | 443 | https://variti.io |
| Negate | 414 | https://negate.io |
| PerimeterX | 401 | https://www.perimeterx.com |
| GeeTest | 345 | https://www.geetest.com |
| Securiti | 251 | https://securiti.ai |
| NoFraud | 210 | https://www.nofraud.com |
| Basic | 197 | https://tools.ietf.org/html/rfc7617 |
| AntiBot.Cloud | 170 | https://antibot.cloud |
| Solve Media | 168 | https://solvemedia.com |