HTTP Header Checker
Inspect the full HTTP response headers of any URL. Trace redirect chains, score security headers, and audit cache configuration — all in one free tool.
How to Use the HTTP Header Checker
Enter any URL and click Check Headers. The tool fetches the URL server-side, follows any redirects step by step, and returns the full response headers from the final destination. You will see a redirect chain map, a security score card, and a complete table of every header returned.
Security Header Grade Explained
All 6 security checks pass. Excellent configuration.
4–5 checks pass. Minor gaps to address.
2–3 checks pass. Security needs improvement.
0–1 checks pass. Critical security headers missing.
Key Security Headers Reference
| Header | Purpose | Recommended Value |
|---|---|---|
| Strict-Transport-Security | Force HTTPS connections | max-age=31536000; includeSubDomains |
| X-Frame-Options | Prevent clickjacking | SAMEORIGIN or DENY |
| Content-Security-Policy | Block XSS & injection attacks | custom per site |
| X-Content-Type-Options | Prevent MIME sniffing | nosniff |
| Referrer-Policy | Control referrer data | strict-origin-when-cross-origin |
| Permissions-Policy | Restrict browser feature access | custom per site |
Common HTTP Header Issues That Affect SEO
- •Redirect chains longer than 3 hops slow crawl budget and dilute link equity.
- •Missing Cache-Control headers force crawlers and browsers to re-fetch static assets unnecessarily.
- •X-Robots-Tag: noindex in headers overrides any on-page meta robots tag — easy to miss.
- •Server header exposing software versions (e.g. Apache/2.4.51) is a security risk.
- •No HTTPS redirect means some users may access your site over plain HTTP, hurting trust signals.
Frequently Asked Questions
What are HTTP response headers and why do they matter for SEO?
HTTP response headers are metadata sent by a web server alongside every page response. They tell browsers and search engine crawlers how to handle the content — including how long to cache it, whether it can be framed by another page, and what security policies apply. Headers like Cache-Control affect page speed (a Google ranking factor), and an X-Robots-Tag set to 'noindex' can prevent a page from appearing in search results entirely.
What is an HSTS header and why should I enable it?
HSTS (HTTP Strict Transport Security) is a response header that instructs browsers to only connect to your site over HTTPS, even if a user types 'http://' manually. Without HSTS, users can be vulnerable to SSL-stripping attacks on insecure networks. Enabling HSTS also signals to search engines that your site is committed to secure connections, which is a minor positive trust signal.
How does Cache-Control affect SEO and performance?
The Cache-Control header tells browsers and CDN proxies how long to store a resource before re-fetching it. Proper caching reduces server response times and page load times — both of which directly influence Google's Core Web Vitals scores. Static assets like CSS, JS, and images should typically be cached for 1 year (max-age=31536000), while HTML pages often use shorter durations or 'no-store' for dynamic content.
What does a 301 vs 302 redirect mean for SEO?
A 301 redirect is permanent and passes approximately 99% of the original page's link equity (PageRank) to the destination URL. A 302 redirect is temporary and historically passed less or no link equity, though Google now often treats them similarly. Use 301 for permanent moves (e.g., HTTP to HTTPS migration, domain changes) and 302 only when you genuinely plan to revert the redirect.
What is the Content-Security-Policy header?
Content-Security-Policy (CSP) is a security header that restricts which external resources (scripts, stylesheets, images, fonts) a browser is allowed to load on your page. A strict CSP dramatically reduces the risk of cross-site scripting (XSS) attacks. While CSP is not a direct SEO ranking factor, sites that are hacked and serve malicious content risk manual actions from Google, which can cause complete de-indexing.
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