HTTP Security Headers Checker
An HTTP security headers checker evaluates the defensive security response headers transmitted by a web server. It audits critical protections including Strict-Transport-Security (HSTS), Content-Security-Policy (CSP), X-Frame-Options, and X-Content-Type-Options, grading your configuration to shield visitors from clickjacking, MIME-sniffing, and code injection attacks.
Inspects live response headers against modern OWASP and RFC web security standards.
Evaluation completed against OWASP best practices.
Security Headers Checklist
What is a HTTP security headers checker and when should you use it?
Modern web browsers rely on HTTP response headers defined by RFC standards and W3C recommendations to activate client-side security sandboxes. Without headers like Strict-Transport-Security (HSTS), visitors are vulnerable to SSL-stripping attacks. Without Content-Security-Policy (CSP), malicious third-party scripts can execute cross-site scripting (XSS) payloads. Without X-Frame-Options, rogue websites can overlay invisible frames to orchestrate clickjacking attacks. Search engines increasingly prioritize secure, resilient website architectures in page experience signals. Use this checker to probe live website headers, or verify your SSL redirection with the HTTP to HTTPS Redirect Checker and audit redirect hops using the Redirect Chain Checker. For raw server header inspection, run the HTTP Status Code Checker.
How do you use it?
- Enter your website address into the audit input field.
- Click the Audit Security Headers button to fetch live server response metadata.
- Review your overall security score and compliance letter grade.
- Inspect the detailed breakdown for HSTS, CSP, X-Frame-Options, and Referrer-Policy.
- Copy recommended configuration directives and apply them to your web server (Apache, Nginx, or Cloudflare).
Working on a comprehensive technical audit? Browse all free SEO tools to discover the next step in your workflow, or contact our technical support team if you require a specialized custom utility.
Result interpretation & practical applications
When evaluating the output of the HTTP security headers checker, review the parsed metrics against your specific site architecture. Outputs are formatted for direct implementation into your HTML source, web server configuration, or Google Search Console audit files.
Always inspect generated values for contextual nuance. Automated tools highlight structural patterns, but manual verification confirms that technical directives align with your overarching SEO strategy.
Technical rules and limitations
- Strict-Transport-Security (HSTS) must specify a minimum `max-age` of 31536000 seconds (1 year) and includeSubDomains for preloading eligibility.
- Content-Security-Policy (CSP) restricts executable script origins; avoiding `unsafe-inline` is critical for high-grade protection.
- X-Frame-Options should be set to `DENY` or `SAMEORIGIN` to prevent iframe embedding.
- X-Content-Type-Options must be set to `nosniff` to prevent browsers from executing non-script files as scripts.
Common mistakes and troubleshooting
- Setting HSTS headers on unencrypted HTTP connections where browsers ignore the directive.
- Deploying an overly restrictive Content-Security-Policy that inadvertently breaks legitimate third-party fonts or payment processors.
- Omitting Permissions-Policy, leaving browser hardware features (like camera and microphone) accessible to embedded widgets.
- Relying solely on WordPress security plugins instead of configuring persistent server-level HTTP headers in Nginx or Apache.
No tool can promise how a search engine will crawl, index, or rank your pages. This tool generates and validates code against documented technical specifications; you determine where to deploy it, and you should always test changes on staging environments first. Google publishes extensive guidelines in Search Central on evaluating third-party SEO tools and advice. Learn more about our technical testing standards on our about us page, or explore full site audits on our pricing page.
Related free tools & workflows
Browse all Technical SEO Audit Tools →Technical SEO Audit Workflows
Indexability & Crawling
Redirects & HTTP Headers
Authoritative Technical Documentation & Standards
This tool executes logic aligned with official technical documentation and search engine webmaster standards:
- MDN Web Docs HTTP Headers Documentation
MDN Web Docs: HTTP Headers Security Overview
Primary engineering source and technical documentation.
- OWASP Secure Headers Project
OWASP: Secure Headers Project Best Practices
Primary engineering source and technical documentation.
HTTP Security Headers Checker questions
What is HSTS preloading? ↓
HSTS preloading is a program where Google Chrome, Firefox, and other major browsers bake your domain directly into the browser binary as HTTPS-only, ensuring that even the very first connection is never made over unencrypted HTTP.
Does having security headers directly improve Google rankings? ↓
While security headers are not a direct standalone ranking factor, they prevent security compromises, malware defacements, and SSL warnings that trigger immediate ranking demotions and browser block screens.
Can I configure security headers via Cloudflare Transform Rules? ↓
Yes. Cloudflare Transform Rules allow you to inject HTTP response headers at edge locations without modifying your origin web server configuration.
Is this tool free? ↓
Yes. It is completely free to use and requires no registration or subscription.
Does this tool visit my website or store my files? ↓
No. It executes entirely in your local browser runtime. Your inputs and results are never stored or logged on our servers.
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