WHMCS's default captcha option displays an image with six characters on a striped background. This option does not require additional configuration or an additional account with a captcha service.
Enable hCaptcha or Invisible hCaptcha as your captcha type in WHMCS. hCaptcha offers checkbox-based and invisible captcha options to help you prevent bots from placing orders, creating accounts, or logging in to your Client Area or Admin Area. Before enabling hCaptcha or Invisible hCaptcha in WHMCS, you must configure it in your hCaptcha account.
Enable reCAPTCHA v3 as your captcha type in WHMCS. reCAPTCHA v3 is an invisible captcha type that can help you prevent bots from placing orders, creating accounts, or logging in to your Client Area or Admin Area. Before enabling reCAPTCHA v3 in WHMCS, you must configure it in your Google® account.
The system character set determines how WHMCS handles many special characters. If you alter this value in your WHMCS configuration, you must also save the relevant language files again using the new character set.
When you move your WHMCS installation from one subdomain to another on the same server, you may need to perform additional steps like updating your license.
As your database size increases, you may experience slower page loads and other speed-related issues. Optimizing your database and reducing unnecessary data can help WHMCS run faster.