100% Free Technical SEO & Security Audit Tool

HTTP Headers Checker

Analyze HTTP response headers, status codes, CORS directives, and security configurations instantly. Perfect for debugging web servers, SEO audits, and security compliance.

AI EXECUTIVE SUMMARY & TOP TAKEAWAYS

What Is an HTTP Headers Checker?

An HTTP Headers Checker is a specialized web diagnostic utility that inspects metadata headers returned by a web server upon receiving an HTTP/HTTPS request. As defined by MDN Web Docs and IETF HTTP standards, response headers control browser caching behavior, transport security policies (HSTS, CSP), content encoding, and server status codes.

  • Target Audience: Sysadmins, Developers & Technical SEOs
  • Key Directives: HSTS, CSP, X-Frame-Options & CORS
  • Execution: Real-time Server Probe & Analysis
  • Related Suite:Website Tools Collection
Security Audit Status
6/6
Core Headers Evaluated

Inspect Website HTTP Response Headers

Quick Test:
Analyzing HTTP Headers...

Establishing connection and inspecting server response directives.

Unable to Check Headers
Audit Report

HTTP Response Audit Results

Security Header Audit

Raw Response Headers

HTTP HeaderValue

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How to Use the HTTP Headers Checker

  1. Enter Website URL: Type or paste any valid domain or web page address into the input field (e.g., https://example.com).
  2. Click "Check Headers": Initiate a real-time HTTP server query to retrieve all response directives.
  3. Review Security Analysis: Examine the security scorecard to verify critical headers like HSTS, CSP, and X-Frame-Options.
  4. Inspect Caching & Server Directives: Review status codes, server signatures, Content-Type, and Cache-Control headers.
đź’ˇ Pro Tip: Missing security headers like Strict-Transport-Security or Content-Security-Policy can expose your site to clickjacking, XSS attacks, and SSL downgrade vulnerabilities. Use our Website Management Tools suite for continuous monitoring.

100 Most Common HTTP Response Headers

Complete reference guide for HTTP response headers based on real-world usage statistics.

Frequency CountHTTP HeaderDescription
834,082Content-TypeDenotes the type of media attached to response
833,384DateDate and time the server generated the response
786,517ServerInformation about backend server software
753,241Set-CookieAssigns cookies from server to client session
714,923ConnectionControls network connection lifecycle
706,267Content-EncodingSpecifies payload compression (gzip, br, deflate)
628,732VaryDetermines request headers used for cache validation
518,756Cache-ControlDirectives for browser and CDN proxy caching
501,318Transfer-EncodingEncoding format used for safe data transfer
368,014ExpiresExpiration date/time for cached response
334,063Content-LengthSize of payload body in bytes
307,086X-Powered-ByHosting or application framework version signature
298,609LinkSerializes web relationships and preloads in headers
235,691PragmaLegacy header for backwards-compatible caching
226,452Keep-AliveSpecifies persistent connection timeout parameters
208,912Last-ModifiedLast modification timestamp used for caching
157,980X-Content-Type-OptionsPrevents MIME-type sniffing vulnerabilities
128,658CF-RAYCloudflare request routing hash and data center ID
128,187ETagEntity tag identifier for cache validation
127,715X-Frame-OptionsProtects site against iframe clickjacking
126,487CF-Cache-StatusCloudflare CDN edge cache hit/miss status
122,831Accept-RangesIndicates server support for byte-range requests
119,876Strict-Transport-SecurityForces browser communication over HTTPS (HSTS)
118,843X-XSS-ProtectionLegacy Cross-Site Scripting filter directive
104,121Expect-CTCertificate Transparency enforcement and reporting
69,989X-CacheCDN cache hit or miss status indicator
55,989AgeTime in seconds resource has spent in proxy cache
42,154Content-Security-PolicyRestricts external script and resource loading (CSP)
30,872Access-Control-Allow-OriginCORS origin sharing permission directive
29,572Referrer-PolicyControls HTTP Referer information sent in requests

Understanding Non-Standard ("X-") Headers

Headers prefixed with "X-" are custom non-standard headers. Although not part of official IETF HTTP specifications, they are widely used by web frameworks, reverse proxies (e.g. NGINX, Varnish), and CDNs (Cloudflare, AWS CloudFront) to pass telemetry data.

Common Examples: X-Powered-By, X-Frame-Options, X-Cache, X-Request-Id
FAQ Guide

Frequently Asked Questions

High-intent answers to common questions about HTTP response headers and security audits.

Direct Answer:

HTTP response headers are metadata key-value pairs returned by a web server alongside requested content. They convey critical instructions regarding browser caching, transport layer security, content encoding, and server software signatures. Inspecting them ensures your server is properly configured and secured against web vulnerabilities.

Direct Answer:

Essential security headers include Strict-Transport-Security (HSTS), Content-Security-Policy (CSP), X-Frame-Options, X-Content-Type-Options, Referrer-Policy, and Permissions-Policy. Implementing these headers mitigates Cross-Site Scripting (XSS), clickjacking, and protocol downgrade attacks.

Direct Answer:

Enter your website domain URL into our free HTTP Headers Checker tool. The security audit scorecard will instantly inspect and report whether the Strict-Transport-Security header is active and returning valid max-age directives.

Direct Answer:

200 OK indicates successful resource processing by the web server, 301 Moved Permanently signals permanent URL redirection for search engine indexation, and 404 Not Found signifies that the requested resource could not be found on the server.

HTTP Header Check API Documentation

Programmatically check HTTP headers and security parameters for any domain using our REST API endpoint.

API Endpoint

GEThttps://www.operatetools.com/http-headers-checker/check?url={URL}

Example Usage

JavaScript (Fetch API)
fetch('https://www.operatetools.com/http-headers-checker/check?url=https://example.com')
  .then(res => res.json())
  .then(data => {
    console.log('Headers:', data.headers);
    console.log('Security:', data.security);
  });
cURL Terminal
curl "https://www.operatetools.com/http-headers-checker/check?url=https://example.com"