HTTP Security Headers Analyzer
Analyze the security headers of any website. Detect missing headers and get recommendations for hardening.
How to Use the HTTP Headers Checker
- Enter the URL of the website you want to analyze.
- The tool fetches and analyzes all HTTP response headers.
- Review the security grade and list of present and missing security headers.
- Read the specific recommendations for each missing or misconfigured header.
- Implement the suggested headers in your server configuration.
Why HTTP Security Headers Matter
HTTP security headers are response headers that instruct browsers to enable specific security mechanisms. They form a critical defense layer that protects your website and its users against common web attacks. Even if your application code is secure, missing security headers leave the browser without important protections against XSS, clickjacking, MIME type attacks, and protocol downgrade attacks. Key security headers include Strict-Transport-Security (HSTS) which enforces HTTPS connections, Content-Security-Policy (CSP) which prevents XSS and data injection, X-Frame-Options which blocks clickjacking, X-Content-Type-Options which prevents MIME sniffing, Referrer-Policy which controls information leakage in referrer headers, and Permissions-Policy which restricts access to browser features like camera, microphone, and geolocation. Security headers are one of the easiest and most impactful security improvements you can make. They require no code changes to your application, only server configuration updates. During security assessments and penetration tests, missing security headers are among the first findings reported. Tools like this header checker and Mozilla Observatory help you identify gaps and prioritize which headers to implement. Start with HSTS and CSP for the highest security impact, then add the remaining headers for comprehensive protection.
Frequently Asked Questions
Start with Strict-Transport-Security (HSTS) to enforce HTTPS, and Content-Security-Policy (CSP) to prevent XSS. Then add X-Content-Type-Options: nosniff, X-Frame-Options (or CSP frame-ancestors), and Referrer-Policy. Finally, add Permissions-Policy to restrict unnecessary browser API access. Each header addresses different attack vectors.
HTTP Strict Transport Security tells browsers to only connect to your site over HTTPS, even if a user types http://. This prevents SSL stripping attacks where an attacker downgrades the connection to HTTP to intercept traffic. Include the includeSubDomains directive and consider HSTS preloading for maximum protection.
Most sites score poorly because they only serve basic headers and miss security-specific ones. Common omissions include CSP (complex to implement), HSTS (requires full HTTPS commitment), Permissions-Policy (relatively new), and Referrer-Policy. Each missing header represents an unmitigated attack surface that browsers cannot protect against.
Yes, if misconfigured. A strict CSP can block legitimate scripts and styles. HSTS with a long max-age on a site not fully committed to HTTPS can cause accessibility issues. Always test headers in a staging environment first, use CSP report-only mode initially, and start with short max-age values for HSTS before increasing them.