Security Headers and SEO

What security headers do

Security headers are HTTP response headers that tell browsers how to handle your content. They help prevent attacks like cross-site scripting, clickjacking and data injection. Common examples include Content-Security-Policy, X-Frame-Options, and Strict-Transport-Security.

These headers do not directly affect search rankings. Search engines do not parse them for ranking signals. However, a site that serves malware or gets compromised may be flagged or removed from search results, and security headers are part of preventing that.

Strict-Transport-Security and HTTPS

The Strict-Transport-Security header (HSTS) tells browsers to only connect to your site over HTTPS, even if someone types http:// in the address bar. This prevents downgrade attacks. HTTPS itself is a confirmed ranking signal.

SEOAST checks whether your page loads over HTTPS with a valid certificate. The presence or absence of the HSTS header is noted but does not change your score, because HTTPS alone is what search engines measure.

Content-Security-Policy

A Content-Security-Policy (CSP) header restricts which scripts, styles and other resources the browser will load. A strict CSP makes injection attacks much harder. It has no direct SEO benefit, but it protects the integrity of the page search engines index.

A misconfigured CSP can break your page, which would harm SEO indirectly. SEOAST does not validate CSP syntax because that is a security tool's job, not an SEO audit's.

X-Frame-Options and clickjacking

The X-Frame-Options header prevents your page from being embedded in an iframe on another site, which defends against clickjacking. Like other security headers, it does not affect rankings but protects the page from being misused.

What SEOAST checks

The transport_security check verifies that your page loads over HTTPS with a valid certificate. Security headers beyond HTTPS are reported where relevant but do not contribute to the score, because search engines do not rank on them.