Header Checker: See Every HTTP Response Header
An HTTP header checker shows every response header a URL returns, including the first response if it redirects. SEO-critical headers are pulled out and explained: X-Robots-Tag, Link (canonical), Content-Type, Cache-Control, compression and HSTS. Enter a URL to see them.
We request the URL live and show the raw headers exactly as your server or CDN returned them. Free, no signup. Updated Oct 24, 2026 by the AEOeye team.
HTTP Header Checker: X-Robots-Tag, Cache and Redirects
Most headers don't matter for SEO; a few matter a lot because they can override what your HTML says.
| Header | Why it matters |
|---|---|
| X-Robots-Tag | Can noindex a page (or a PDF) without any meta tag |
| Link | Can declare rel=canonical or hreflang, mainly for non-HTML files |
| Location | The redirect target on 3xx responses |
| Content-Type | Pages must be text/html to be parsed as HTML |
| Cache-Control / ETag | Repeat-visit speed and efficient recrawling |
| Content-Encoding | gzip or brotli compression |
| Strict-Transport-Security | Forces HTTPS on future visits |
Google documents X-Robots-Tag as equivalent to the robots meta tag — and it's the only option for files without HTML.
HTTP Headers Check: What Each Header Does to SEO
The dangerous one is X-Robots-Tag, because it's invisible in the page source. A noindex header left over from staging removes pages from Google while the HTML looks perfectly fine.
It's rare on homepages — 2.9% of the 315 homepages we analyzed in October 2026 sent an X-Robots-Tag (dataset) — but much more common on PDFs, feeds and environments copied from staging.
Is my site compressing pages?
Check Content-Encoding. In our sample, 59% of homepages were served with brotli, 37.1% with gzip and 3.8% uncompressed. Uncompressed HTML is a free speed win waiting to happen: turning on gzip or brotli is usually a single server or CDN setting.
How do I read the result?
Start with the status line, then the flagged SEO headers, then the full list. If the URL redirects, we also show the first response, because headers on a redirect (like a stray noindex) can matter too.
For definitions of any header you don't recognize, MDN's header reference is the standard. To check the security headers specifically and get a grade, use the security headers checker; for indexing directives in both tags and headers together, use the meta robots checker.
One page checked. What about the rest of your site?
The free SEO audit crawls your site and scores ~90 checks across 7 areas — with the evidence and the fix for each problem.
FAQ
How do I check the HTTP headers of a website?
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Enter the URL above. You can also use your browser's developer tools (Network tab) or run curl -I with the URL in a terminal to see the response headers.
Can an HTTP header noindex my page?
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Yes. An X-Robots-Tag: noindex header tells Google not to index the URL, exactly like a robots meta tag, and it works on PDFs and images that can't carry meta tags.
Why do headers differ between this tool and my browser?
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CDNs can vary responses by location, device, cookies or user agent, and browsers add cached responses. We show what a fresh request from our server receives.
Sources
Related free tools
Security Headers Checker
Free security headers checker: scan a URL for HSTS, CSP, X-Frame-Options, X-Content-Type-Options and more, graded A–F with copy-paste fixes.
Meta Robots Checker
Check a page's meta robots tag and X-Robots-Tag header together — noindex, nofollow, nosnippet, max-image-preview — and which one Google obeys.
Redirect Checker
Free redirect checker: paste a URL to see every hop, status code (301/302/307/308), timing and loops — and whether the chain hurts SEO. No signup.
HSTS Checker
What is HSTS and is yours right? Check any site's Strict-Transport-Security header, max-age, includeSubDomains and preload eligibility, with fixes.