XSS Validator

Detect and sanitize potential Cross-Site Scripting vulnerabilities

xsscross-sitescriptingsecurityvalidationsanitizeinjection

XSS Vulnerability Scanner

Detect and prevent Cross-Site Scripting attacks. Test your inputs against common XSS patterns and get instant security recommendations.

Instant validation
100% client-side
12+ XSS patterns

XSS Prevention Best Practices

Input Validation

  • Validate all input on the server side
  • Use allowlists instead of blocklists
  • Reject invalid input rather than sanitizing

Output Encoding

  • HTML encode for HTML context
  • JavaScript encode for JS context
  • URL encode for URL context

Security Headers

  • Use Content Security Policy (CSP)
  • Enable X-XSS-Protection header
  • Set X-Content-Type-Options
Learn more about XSS prevention