HTTP header checker

Inspect every redirect with the HTTP header checker. Review security grades and cookie flags, then compare browser and crawler responses.

Free, no account. Ten site checks per hour.

Our server requests the page, follows up to 8 redirects and reads the headers. Results can be cached for five minutes.

For a crawler, we also ask as a browser and compare.

An HTTP header checker requests a page and lists the headers the server sends back. This one follows redirects, groups caching, security and SEO headers, and explains each one. Choose a browser, Googlebot, Bingbot or an AI crawler as the visitor. For a crawler, we also ask as a browser and say when the answers differ.

How to use this checker

Enter a page and choose the visitor
Paste a public page address. Pick Browser to see what people get, or a crawler to see what the server sends to Googlebot, Bingbot, GPTBot, OAI-SearchBot, ClaudeBot or PerplexityBot. We send that crawler’s published user agent from our own server.
Read the groups
Caching headers decide how long browsers and CDNs keep a copy. Security headers protect visitors against injected scripts, framing and insecure connections. SEO headers tell crawlers about indexing, the canonical address, the character set and compression. Everything else is listed as sent.
Compare a crawler with a browser
When you pick a crawler, we request the same page as a browser too. A different status or a bot check page for one of them usually comes from a firewall or bot rule. Google and Bing verify their crawlers by IP address, which our server cannot match, so a block of our request points to a firewall or CDN rule to review.

Questions about this checker

Firewalls, CDNs and bot protection often filter by user agent. Some sites block AI crawlers on purpose, others through a default rule nobody chose. If the crawler gets a 403 or a challenge page while the browser gets a 200, look at the bot settings at your CDN or host.

Not necessarily. Cloudflare and other CDNs check Googlebot and Bingbot by IP address, and our requests do not come from Google or Bing addresses. Treat the block as a reason to review your firewall rules, then confirm with the URL Inspection tool in Google Search Console.

Strict-Transport-Security on HTTPS sites, X-Content-Type-Options set to nosniff, a frame-ancestors rule or X-Frame-Options against clickjacking, and a Referrer-Policy. A Content-Security-Policy gives the strongest protection, but test it first, because a strict policy can stop scripts on the page from running.

Some do. An X-Robots-Tag header with noindex keeps a page out of search even when the HTML looks fine. A Link header can declare the canonical address. A wrong character set can garble text, and missing compression makes pages slower to download.

Related tools

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    Use this SSL certificate checker to inspect a live certificate and its chain. Review TLS support and HTTPS policy, then save an expiry reminder.

  • Redirect checker

    Use this redirect checker to inspect HTTP chains for up to 100 URLs. Compare crawler and browser responses, then review loops and canonical conflicts.

  • User agent checker

    Use this user agent checker to inspect your browser or up to 50 pasted strings. Read browser, engine and OS tokens, frozen-version warnings and documented crawler matches.

Check your business in AI answers

Technical checks help you repair a page. The free AI visibility scan shows the answers checked for your business and what to work on next.

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