Free HTTP Header Checker
Inspect security, caching & SEO response headers.
What is the HTTP Header Checker?
Every response your server sends carries headers the browser acts on before a single pixel renders — whether to force HTTPS, how long to cache, whether to allow framing, how to compress. Get them wrong and you leave performance on the table and security holes wide open, all invisibly.
This HTTP header checker fetches any URL and lays out its response headers, grouped and graded, so you can see what's protecting your site and what's missing.
Last updated: Aug 13, 2026
What does this tool do?
You enter a URL and the tool makes a request and reads the response headers, then sorts them into security, caching, performance and server groups.
It highlights which key headers are present or missing, explains what each does, gives a security-header coverage score, and lists every raw header returned.
Key features
Security headers
HSTS, CSP, X-Frame-Options and more.
Coverage score
A quick percentage of key security headers present.
Caching & compression
Checks Cache-Control, ETag and gzip/Brotli.
Info-leak check
Flags X-Powered-By and server version exposure.
All raw headers
Expand to see every header returned.
Example
Common use cases
- Developers — Verify security headers ship in production.
- DevOps — Confirm caching and compression are configured.
- Security-minded owners — Harden a site against common attacks.
- SEO specialists — Check compression and caching that affect speed.
- Agencies — Audit a client's header hygiene.
- Site owners — See whether the server leaks its stack.
- QA engineers — Catch missing headers before a release.
- Anyone debugging caching — Read the exact Cache-Control served.
Benefits
- It reveals security gaps you can't see in a browser.
- It confirms compression and caching are actually on.
- It flags headers that leak your technology stack.
- It explains what each header does, not just whether it's there.
Tips
- Add Strict-Transport-Security to force HTTPS on repeat visits.
- Set X-Content-Type-Options: nosniff to stop MIME sniffing.
- Use a Content-Security-Policy to reduce XSS risk.
- Prevent clickjacking with X-Frame-Options or CSP frame-ancestors.
- Enable gzip or Brotli compression to shrink transfers.
- Set sensible Cache-Control so static assets cache well.
- Remove X-Powered-By and server version headers to avoid leaking your stack.
- Re-check after infrastructure or CDN changes.
Common mistakes to avoid
No HSTS header
Fix: Add Strict-Transport-Security so browsers force HTTPS on future visits.
Missing compression
Fix: Enable gzip or Brotli on your server or CDN to speed up transfers.
Leaking the tech stack
Fix: Remove X-Powered-By and server version details from responses.
No caching headers
Fix: Set Cache-Control and ETag so browsers and CDNs cache efficiently.
How it works
- 1
Enter a URL
Any page or endpoint.
- 2
Check
It reads the response headers.
- 3
Harden
See which headers are missing and why they matter.
Frequently asked questions
Security headers (HSTS, CSP, X-Content-Type-Options, X-Frame-Options, Referrer-Policy, Permissions-Policy), caching, compression, content type, and server headers.
The percentage of key security headers present on the response — a quick gauge of your header hardening.
Security headers (HSTS, CSP, X-Content-Type-Options, X-Frame-Options, Referrer-Policy, Permissions-Policy), caching, compression, content type, and server headers.
The percentage of key security headers present on the response — a quick gauge of how hardened your headers are.
Indirectly. Compression and caching affect page speed, and HTTPS is a ranking signal — all reflected in headers.
It advertises your server software and version, giving attackers a head start. Removing it is a simple hardening step.
Any publicly reachable URL. Endpoints behind authentication may return different headers.
No. Headers are read from a single request and nothing is saved.
Conclusion
An HTTP header checker turns invisible response headers into a clear, graded checklist so you can harden security and tighten performance. Pair it with the whole-site SEO audit and redirect checker for full technical health.