HTTP Header Checker
Fetch any URL and inspect all HTTP response headers returned by the server. View status codes, security headers (HSTS, CSP, X-Frame-Options), caching directives (Cache-Control, ETag), content negotiation headers (Content-Type, Content-Encoding), and CORS policies with plain-English descriptions for every header. Our tool sends a HEAD request from your browser (no server proxy) and grades your site's security posture from A to F - no signup required.
Fetch any URL and inspect all HTTP response headers. View status codes, security headers, caching directives, CORS policies, and more with detailed descriptions for each header.
Enter a URL to inspect its HTTP response headers (https:// is added automatically if missing)
Why Use Our HTTP Header Checker?
Complete HTTP Header Inspection
Fetch any URL and inspect all response headers returned by the server. See status codes, content-type, cache-control, server info, and every custom header with their raw values for full transparency.
Security Header Analysis & Grade
Automatically detect and grade security headers including HSTS, CSP, X-Frame-Options, X-Content-Type-Options, Referrer-Policy, and Permissions-Policy. Get a letter grade (A-F) with actionable recommendations for improving your security posture.
Detailed Header Descriptions
Every header includes a plain-English description explaining its purpose, how it affects browser behavior, and whether it is a recommended best practice. Expand any header to see its full description and raw value with one-click copy.
Organized by Category
Headers are grouped into intuitive categories - Security, Caching, Content, CORS, Connection, Cookie, and General - with colour-coded badges. Quickly find the headers that matter most for security audits, performance tuning, and debugging.
Common Use Cases for HTTP Header Checker
Security Audit & Hardening
Use the HTTP header checker to audit your website's security posture. Check for missing HSTS, CSP, X-Frame-Options, and other critical security headers that protect against XSS, clickjacking, and data injection attacks.
CORS Debugging
When your frontend can't access an API due to CORS errors, use this tool to inspect the Access-Control-* headers returned by the server. Quickly identify missing origins, methods, or headers in the CORS configuration.
Cache Configuration Verification
Verify that your CDN and web server are sending the correct Cache-Control, ETag, and Expires headers. Ensure static assets are properly cached and dynamic content is served fresh as expected.
Redirect Chain Analysis
Check if URLs are returning redirects (301, 302, 307, 308) by inspecting the Location header. Verify that redirects point to the correct URLs and that the redirect chain terminates as expected.
HTTPS & HSTS Verification
Confirm that your site enforces HTTPS by checking for the Strict-Transport-Security header. Verify the max-age, includeSubDomains, and preload directives are correctly configured.
Server & Technology Fingerprinting
Identify the server software, programming framework, and caching layers used by any website. Check the Server, X-Powered-By, and custom headers to understand the technology stack powering a site.
Understanding HTTP Headers
What Are HTTP Headers?
HTTP headers are the metadata of web communication. When your browser requests a webpage, the server responds with a set of headers before sending the actual content. These headers tell the browser how to interpret the response,how long to cache it, what security policies to enforce, and what origins are allowed to access it. Headers like Content-Type (what kind of data is returned), Strict-Transport-Security (enforce HTTPS), and Cache-Control (caching rules) are essential for modern web performance and security.
How Our HTTP Header Checker Works
- Enter a URL: Type any URL (with or without https://) and click "Check Headers". We automatically add https:// if no protocol is specified and send an HTTP HEAD request from your browser.
- Header Collection: The target server returns its response headers without the body. We capture all headers including status code, timing information, and every key-value pair the server sends.
- Analysis & Grading: Each header is categorized, described, and flagged if it's a recommended security practice. A letter grade (A-F) is calculated based on the presence of six critical security headers: HSTS, CSP, X-Frame-Options, X-Content-Type-Options, Referrer-Policy, and Permissions-Policy.
HTTP Status Code Classes
- 1xx (Informational): The request was received and is being processed. Rarely seen in normal browsing.
- 2xx (Success): The request was successfully received, understood, and accepted. 200 OK is the standard success response.
- 3xx (Redirection): Further action is needed to complete the request. 301 Moved Permanently and 302 Found are common redirects.
- 4xx (Client Error): The request contains bad syntax or cannot be fulfilled. 404 Not Found and 403 Forbidden are common examples.
- 5xx (Server Error): The server failed to fulfill a valid request. 500 Internal Server Error indicates a server-side problem.
Privacy, Security & Availability
Our HTTP Header Checker sends requests directly from your browser to the target server. We do not proxy, store, log, or process any URL checks on our servers. The tool is 100% free with no signup, no account, and no usage limits. All header parsing and security grading happens client-side in your browser. Note that some servers may block HEAD requests or have CORS restrictions that prevent browser-side fetching, which may cause certain URLs to fail.
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Frequently Asked Questions About HTTP Header Checker
HTTP headers are key-value pairs sent between the client and server in every HTTP request and response. Response headers contain metadata about the server, the resource being served, caching instructions, security policies, and connection information. Headers like Content-Type, Cache-Control, and Strict-Transport-Security control how browsers handle and display web content.
Enter a URL and click "Check Headers". Your browser sends a HEAD request to the URL, which retrieves the response headers without downloading the full page body. The headers are parsed, categorized, and displayed with descriptions. A security grade (A-F) is calculated based on the presence of recommended security headers.
A HEAD request fetches only the response headers without downloading the response body. This is faster and uses less bandwidth. The headers returned by a HEAD request are identical to what a GET request would receive, so you get the same information without the overhead of downloading the full page.
The six key security headers are: Strict-Transport-Security (HSTS) for HTTPS enforcement, Content-Security-Policy (CSP) for XSS protection, X-Frame-Options for clickjacking prevention, X-Content-Type-Options to prevent MIME sniffing, Referrer-Policy for privacy control, and Permissions-Policy for API access control. Our tool grades your site A-F based on these six headers.
The grade (A-F) reflects how many of the six recommended security headers your site returns. A (6/6) means all major security headers are present. B (4-5/6) means most are present. C (3/6) means some are missing. D (2/6) means few are present. F (0-1/6) means critical security headers are missing and your site may be vulnerable to common web attacks.
No. Your URL checks go directly from your browser to the target server. We do not store, log, or process your queries on any server. The HEAD request is made from your browser, and all header analysis happens client-side.
Some servers may block HEAD requests, require authentication, or have CORS restrictions that prevent browser-side fetching. Additionally, if the server is down, unreachable, or times out, the header check will fail. Try a different URL or confirm the URL is accessible from a regular browser window.
Yes! 100% free with no signup, no account, and no usage limits. Check HTTP headers for any URL as many times as you need.