View every HTTP response header a website sends — general, caching, security, cookies, and server headers, grouped and explained. Free to use • No account required.
✍️ Author: ToolsNovaHub•📅 Last Updated: 14 September 2026•🔧 Methodology: live GET request via server-side proxy, max 10 redirects, 10s timeout, private/internal IPs blocked at every hop
Examples:
github.comwikipedia.org
🔄 Fetching response headers…
📊 Response Summary
HTTP Status—
Final URL—
Total Headers—
📄 General
Header
Value
🔒 Security-Related
Header
Value
💾 Caching
Header
Value
📋 Other Headers
Header
Value
📚 What Are HTTP Response Headers?
Every time a browser requests a page, the server responds with the page content plus a set of HTTP response headers — metadata describing the response itself: what type of content it is, how long it can be cached, what server software generated it, what security policies apply, and more. Headers are invisible in the rendered page but fully readable by browser developer tools and dedicated inspectors like this one.
📋 Common Header Categories
Category
Example Headers
Purpose
General
Content-Type, Content-Length, Date
Basic response metadata
Caching
Cache-Control, ETag, Expires, Last-Modified
Controls how browsers and CDNs cache the response
Security
HSTS, CSP, X-Frame-Options
Browser-enforced defensive instructions
Server Info
Server, X-Powered-By
Reveals (often unintentionally) the underlying tech stack
Cookies
Set-Cookie
Instructs the browser to store a cookie for future requests
⚙️ How This Checker Works
Browsers block JavaScript from reading another site's response headers unless the target explicitly opts in via CORS — almost none do. This tool routes the request through a small, stateless server-side proxy that performs the fetch and relays back exactly what headers came back, unfiltered.
The proxy issues a single standard GET request, identical to what happens when any visitor loads the page in their browser, and does not store the URLs you check. Use this tool only on domains you own or are authorized to review; the response headers themselves are public by default, but treat any site you don't operate the same way you would treat any other system outside your own control.
🔍 Why Results Might Differ From Your Browser
Redirects: if the URL you check returns a 301/302 redirect, this tool shows the headers of that first response, not the final destination — check the status code shown; if it's a redirect, re-run the check against the target URL to see its headers.
CDN or edge caching: a CDN (Cloudflare, Fastly, etc.) can serve a cached response with headers that were captured at an earlier point in time, or can inject/strip headers at the edge that differ from what your origin server actually sent. If headers look unexpected, compare against a cache-busting query string or check your CDN's header-modification rules.
Geographic or A/B routing: some sites serve different headers (or configurations) to different regions or user segments. A result here reflects the response our proxy server received, which may differ from what a visitor in a different location sees.
Missing headers aren't always a misconfiguration: not every header is expected on every site — a static marketing page has different needs than an app handling authentication. Cross-reference against the Security Headers Checker for a scored assessment specific to security-relevant headers.
🛠️ Use Cases
🔧
Debugging Caching Issues
See exactly what Cache-Control and ETag values a page is serving when troubleshooting stale content complaints.
🔍
Competitive Tech Stack Research
Server and X-Powered-By headers can reveal what CDN, framework, or hosting a competitor's site runs on.
🛡️
Pre-Deployment Verification
Confirm all expected headers actually made it to production after a config change, not just the security-critical ones.
🎮
API Response Inspection
Check Content-Type, rate-limit headers, and CORS headers returned by a third-party API you're integrating with.
ToolsNovaHub tools are built and independently maintained with a focus on accurate, no-signup network and security utilities. Spotted an error? Let us know.
🎓
Expert Tip
DNS and mail records can take up to 48 hours to fully propagate — if HTTP Headers Checker shows an unexpected result right after a change, wait and re-check before assuming misconfiguration.
⭐
ToolsNovaHub Pro Tip
Run HTTP Headers Checker from more than one network (office Wi-Fi + mobile data) to rule out local resolver caching before reporting a bug.
⚠️
Common Beginner Mistake
Editing a live DNS or mail record without noting the previous value first. Always save the old record from HTTP Headers Checker's output so you can roll back instantly if something breaks.
A key-value pair a server sends alongside response content, providing metadata like content type, caching rules, server software, and security policy.
What is the difference between this and Security Headers Checker? +
Security Headers Checker grades a curated set of security-relevant headers. This tool shows the complete, unfiltered set of every header returned, grouped by category.
Can I see cookies set by a website with this tool? +
Yes, Set-Cookie is shown if present, though it reflects a fresh unauthenticated request rather than any session-specific cookie from a logged-in session.
Why do I need a proxy to check HTTP headers? +
Browsers block JavaScript from reading another site's headers unless it opts in via CORS. A small server-side proxy performs the fetch and relays results instead.
What is the Content-Type header used for? +
Tells the browser what kind of content is in the response body — text/html, application/json, image/png, etc — so it knows how to render it.
Is checking another website's headers legal? +
Yes — response headers are returned to any client making a normal request, identical to what your own browser receives visiting the site directly.
What does the Server header reveal? +
Often the web server software and sometimes its version (e.g. nginx/1.25) — useful for research, though many sites deliberately obscure or remove this for hardening.
What is ETag used for? +
A unique identifier for a specific version of a resource, letting the browser ask "has this changed?" on a follow-up request instead of re-downloading unchanged content.
Can headers differ between requests to the same URL? +
Yes — A/B tests, CDN edge location, load balancer routing, or server-side personalization can all cause headers to vary slightly between individual requests.
Does this tool follow redirects? +
Yes, the proxy follows redirects and reports the final URL along with the headers from the final response.
Why are some headers missing that I see in browser DevTools? +
A few headers (like Set-Cookie in some configurations) may be restricted from JavaScript access even through a proxy for security reasons — DevTools has direct browser-level access this tool doesn't.
Is this tool useful for API debugging? +
Yes — check Content-Type, rate-limit headers, CORS headers, and caching directives returned by any API endpoint you're integrating with.
Can I check headers on a localhost or internal URL? +
No — the proxy runs on Cloudflare's network and can only reach publicly accessible URLs, not internal or localhost addresses on your own machine.
Is HTTP Headers Checker free? +
Yes — free, no sign-up. It performs a live GET request through the proxy and reports exactly what headers came back; the proxy applies a soft per-IP rate limit to prevent abuse, which normal usage won't hit.
Can I check headers on an HTTP (non-HTTPS) site? +
Yes — the proxy will fetch whichever protocol the URL specifies, or follow a redirect if the site forces HTTPS, and report the final response's headers.