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Free HTTP header checker

HTTP header checker: what your server tells browsers and Google.

Enter any URL. MrKeyword requests it the way a crawler would and lists every response header, with plain findings on status, X-Robots-Tag, compression, caching and common security headers.

Free, no account needed. MrKeyword fetches the page live and shows only what it found.

Built on first-party data from Google and Bing
Search ConsolePageSpeed InsightsBing Webmaster Tools
An explorer discovering useful search ideas with a magnifying glass
A little curiosity goes a long way.
What it checks

What does an HTTP header checker show?

An HTTP header checker sends one request to a URL and shows the response headers the server returns: the HTTP status, redirect count, and each header name and value, sorted alphabetically so you can scan them quickly.

Some headers change SEO directly. X-Robots-Tag can keep a page out of Google and Bing even when the HTML has no noindex tag. A Link header can name a canonical URL. Errors and redirects show up in the status line before you read the HTML.

Others affect speed and trust. Content-Encoding shows whether HTML is compressed. Cache-Control shows how browsers may reuse the response. Security headers such as Strict-Transport-Security, Content-Security-Policy and Referrer-Policy do not replace good content, but they are worth checking on important pages.

In the result

Clear answers,
with the reason shown.

For search engines

Status, robots directives and canonicals.

HTTP status and redirect count, X-Robots-Tag noindex and nofollow, and a canonical URL named in a Link header.

  • X-Robots-Tag explained
  • Link rel=canonical in headers
Speed and security

Compression, caching and hardening.

Content-Encoding (gzip or Brotli), Cache-Control, HSTS, X-Content-Type-Options nosniff, framing protection (CSP or X-Frame-Options) and Referrer-Policy.

  • Uncompressed HTML flagged
  • Missing HSTS on HTTPS
Worked example

Staging noindex left on in a response header.

The fictional northwind-plumbing.example moved its services page to production but left X-Robots-Tag: noindex on from staging. The HTML has no meta robots tag, and the server sends uncompressed HTML with no HSTS. Checking https://northwind-plumbing.example/services/ gives:

https://northwind-plumbing.example/services/1 problem
  • ProblemX-Robots-Tag: noindex keeps this page out of Google and Bing, even without a noindex meta tag.
  • FixNo Strict-Transport-Security (HSTS) header. Browsers may still open the site over HTTP on the first visit.
  • FixThe HTML is sent uncompressed. Turn on gzip or Brotli on the server so pages load faster for visitors and crawlers.
  • NoteContent-Type is text/html but does not name a charset. Add charset=utf-8 so every browser reads the encoding the same way.
  • NoteNo X-Content-Type-Options: nosniff header. Older browsers may MIME-sniff the response.
  • NoteNothing stops other sites framing this page (clickjacking). Add Content-Security-Policy frame-ancestors or X-Frame-Options.
  • NoteNo Referrer-Policy header, so the browser sends the full URL as Referer on outbound links by default.

HTTP 200 · 120 ms · 0 redirects before this answer

2 response headers
HeaderValue
content-typetext/html
x-robots-tagnoindex

Example result for a fictional website (northwind-plumbing.example). It is produced by the checker's own code from the setup described above; run the checker for your own pages.

The page answers HTTP 200, so it loads for visitors, but the header noindex blocks Google and Bing until it is removed or replaced. That often survives a migration when staging rules stay on the CDN or server. Turn compression on for HTML, add charset=utf-8 to Content-Type, and add HSTS once every URL is on HTTPS. For the rest of an indexing check, use the indexability checker, follow redirects with the redirect checker, or run a full pass with our guide to doing an SEO audit and the free site audit.

Reading the result

How do you read the http header checker result?

The status row
The HTTP status code for the final response after any redirects this request reported, and how long the response took in milliseconds when the server timed it.
The header table
Every response header name and value, sorted alphabetically. Common SEO and security headers are highlighted so they stand out in a long list.
The findings
Short notes labelled Problem, Fix, Note or Good. Errors include X-Robots-Tag noindex and HTTP error statuses; warnings cover missing HSTS and uncompressed HTML; notes cover charset, nosniff, framing and Referrer-Policy.
Redirects
The redirect count is how many HTTP redirects the fetch reported before the final response. For the hop-by-hop path, use the redirect checker.
Common errors

What HTTP header problems affect SEO and security?

X-Robots-Tag: noindex on a live page

Remove the header or change it to index,follow on pages that should rank. Check CDN and cache rules as well as the origin server.

Noindex in the header but not in the HTML

Search engines honour X-Robots-Tag on the response. The indexability checker shows both the header and any meta tag.

HTML sent without compression

Enable gzip or Brotli for text/html on the server or CDN. Smaller responses load faster for visitors and crawlers.

No HSTS on HTTPS

Add Strict-Transport-Security once every URL redirects to HTTPS, so repeat visits stay on a secure connection.

Content-Type without charset

Add charset=utf-8 to text/html responses so browsers and tools read the encoding consistently.

When to check

When should you check response headers?

Check headers when a page should index but does not, when speed drops, or after changing host, CDN or security settings.

After launch or leaving staging
Confirm X-Robots-Tag and Cache-Control from staging did not reach production.
When Search Console shows ‘Excluded by noindex’
See whether noindex comes from X-Robots-Tag, a meta tag, or both.
After turning on HTTPS or a new CDN
Check HSTS, compression and that HTML still has charset=utf-8.
When PageSpeed flags missing compression
Request the HTML URL here and look for Content-Encoding.
Before a security review
Scan HSTS, nosniff, framing policy and Referrer-Policy on login, checkout and account pages.
Go further

Guides for this check.

More free checkers

Other quick checks.

Questions

About the http header checker.

What is an HTTP header checker?

It is a tool that requests a URL once and lists the HTTP response headers the server sends back, together with short notes on headers that affect indexing, speed or security. It does not read the page body beyond what is needed for the request.

What is the X-Robots-Tag header?

X-Robots-Tag is an HTTP response header that carries indexing directives, similar to a meta robots tag. A value such as noindex tells search engines not to include the URL in results, even if the HTML looks indexable.

Do HTTP headers affect SEO?

Some do. X-Robots-Tag can block indexing. A Link header with rel=canonical can point search engines at another URL. Status codes and redirects decide whether a URL is reachable. Compression and caching mostly affect speed and crawl efficiency rather than rankings directly.

How do I check if my site uses gzip or Brotli?

Request a normal HTML URL and look for a Content-Encoding header on the response. gzip or br means the body is compressed. This checker sends Accept-Encoding: gzip, br and reports when HTML comes back with no Content-Encoding.

What security headers should a website have?

There is no single required list, but HTTPS sites often add Strict-Transport-Security, X-Content-Type-Options: nosniff, a policy that limits framing (Content-Security-Policy frame-ancestors or X-Frame-Options) and Referrer-Policy. Exact values depend on your site; this checker flags common gaps so you can decide what to add.