Check the HTTP headers of any URL
Every response header your server sends, plus checks for the ones that affect crawling and indexing: X-Robots-Tag, canonical and hreflang in the Link header, caching, compression and HSTS. Redirects are followed first.
One URL per check. For the full redirect chain with timing and the http, https, www and non-www variants, use the redirect checker.
- 11
- checks on the final response
- 10
- redirects followed, like Googlebot
- €0
- no signup
What the check tests
No scores. Each item says what was found and what it means for search engines, browsers and caches.
- 01
Final status
Redirects are followed hop by hop, up to 10 like Googlebot, and the headers of the response that finally answers are read. For the full chain with timing, use the redirect checker.
- 02
X-Robots-Tag
noindex, nofollow and none, for all crawlers or for one named crawler such as
googlebot:. A noindex sent as a header is invisible in the page source. - 03
Link header
rel="canonical"andrel="alternate"with hreflang, sent as HTTP headers. For PDFs and other files without HTML, this is the only place they can go. - 04
Content-Type and charset
Whether the response says what it is, and whether the character encoding is declared in the header or in a
<meta charset>within the first 1024 bytes of the HTML. - 05
Caching
Cache-Control and Expires, the rules browsers and CDNs follow.
- 06
Compression
Content-Encoding on text responses. Google’s crawlers support gzip, deflate and Brotli.
- 07
ETag and Last-Modified
Validators that let Google’s crawlers ask whether a URL has changed and get a short 304 instead of the full page. Last-Modified has to use the HTTP date format.
- 08
Vary
Vary: User-Agentis right for dynamic serving and fragments caches everywhere else.Vary: *makes a response uncacheable. - 09
HSTS and disclosure
Strict-Transport-Security with its max-age, and Server or X-Powered-By headers that reveal software versions.
Questions
Can an HTTP header keep a page out of Google?
Yes. X-Robots-Tag: noindex has the same effect as a robots meta tag with noindex, and it works for any file type, including PDFs and images. Because it does not appear in the page source, it often goes unnoticed after a server or CDN change. Google only sees it if the URL is not blocked in robots.txt.
Which caching headers does Google’s crawler use?
Google’s crawlers revalidate URLs with ETag and If-None-Match, or Last-Modified and If-Modified-Since. If nothing changed, your server can answer 304 Not Modified without a body, which saves work on both sides. When both are present, Google uses the ETag, and it recommends ETag because it avoids date formatting problems. Cache-Control and Expires mainly matter for browsers and CDNs.
Should the canonical go in the HTTP header or in the HTML?
For HTML pages, the <link rel="canonical"> in the head is the usual choice. The Link header is the method for files without a head, such as PDFs. Google recommends picking one method, because using both at the same time is more error prone. The canonical checker compares both.
Why does the tool not show HTTP/2 or the TLS version?
The check runs on Cloudflare Workers, which do not expose connection details such as protocol version or certificate data. You see the headers an HTTP client receives.
Headers look fine, but pages still don’t rank?
The Search & AI Diagnostic (€290) goes through crawling, indexing, content and AI visibility across your site and tells you what to fix first.