Free Security Headers Checker

HTTP security headers are response headers that instruct browsers how to handle your website content. They matter for SEO because Google uses HTTPS and site security as ranking signals. Missing security headers can lead to clickjacking attacks, content injection, and data theft — all of which can trigger browser warnings that increase bounce rate and hurt rankings. Headers like HSTS ensure visitors always connect via HTTPS, protecting your site's trust signals.

HTTP Strict Transport Security (HSTS) is a header that tells browsers to always connect to your site via HTTPS, even if a user types 'http://' in the address bar. It prevents protocol downgrade attacks and cookie hijacking. For SEO, HSTS ensures all traffic goes through your canonical HTTPS version, avoiding the duplicate content risk of having both HTTP and HTTPS accessible. A typical HSTS header: Strict-Transport-Security: max-age=31536000; includeSubDomains; preload

Content-Security-Policy (CSP) controls which resources your page is allowed to load. It prevents cross-site scripting (XSS) attacks by whitelisting trusted sources. For SEO, a properly configured CSP prevents malicious script injection that could deface your site, insert spam links, or redirect users — all of which can cause Google to flag your site as dangerous, triggering warning pages that destroy your organic traffic.

X-Frame-Options controls whether your page can be loaded inside an iframe on another website. Setting it to 'DENY' or 'SAMEORIGIN' prevents clickjacking attacks. While X-Frame-Options itself is not a direct SEO ranking factor, clickjacking can lead to negative user experiences, fake engagement signals, and potential manual penalties if your site appears to be used for deceptive practices.

How you add security headers depends on your platform. For Nginx: add headers in your server block config. For Apache: use .htaccess with Header set directives. For Vercel: add to vercel.json headers array. For Cloudflare: use Transform Rules or Workers. For WordPress: use plugins like HTTP Headers or add to .htaccess. Always test after adding headers — especially CSP, which can block legitimate resources if misconfigured.