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HTTP Status & Headers Inspector

Audit HTTP response security headers for HSTS, CSP, and caching compliance, and search authoritative RFC 9110 status code references.

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🛡️HTTP Status & Headers Inspector Documentation & Guide

Web & Developer
Hypertext Transfer Protocol (HTTP) status codes and response headers communicate transactional outcomes, caching semantics, and browser security constraints across modern web applications. Misconfigured security headers leave web applications vulnerable to Cross-Site Scripting (XSS), clickjacking, and MIME-sniffing, while improper HTTP status selection damages SEO crawl efficiency and API clients. This tool provides an authoritative RFC 9110 status code lookup and an automated client-side security header auditor.

📋How to Audit Headers & Inspect Codes

  1. Select Mode: Choose between Response Headers Security Audit to test your server's defensive headers, or RFC Status Code Explorer for semantic status lookup.
  2. Input Data: Paste raw HTTP response headers (from cURL, Chrome DevTools, or Postman) or select a status code from the dropdown.
  3. Inspect Security Grade: In Headers mode, review your security score (A+ to F) and check which defense headers (HSTS, CSP, X-Frame-Options, nosniff) are missing.
  4. Verify Caching & Idempotence: In Status Code mode, verify whether the selected code is natively cacheable by proxies or safe for automated retry logic.
  5. Export Report: Click 📋 Copy to copy the diagnostic summary to your clipboard.

⚙️Core Security Headers Baseline (OWASP)

OWASP and Mozilla recommend five foundational defense-in-depth HTTP headers for all production HTTPS origins:

• Strict-Transport-Security: max-age=31536000; includeSubDomains; preload forces HTTPS and blocks SSL stripping attacks.
• Content-Security-Policy: default-src 'self' restricts unauthorized script injection (XSS mitigation).
• X-Content-Type-Options: nosniff prevents browsers from executing non-script MIME types as JavaScript.
• X-Frame-Options: DENY or SAMEORIGIN prevents clickjacking attacks inside malicious iframes.
• Referrer-Policy: strict-origin-when-cross-origin protects sensitive URL query parameters from leaking to third parties.

💡Production & SEO Impact

  • 301 vs. 302 vs. 308: Always use 301 Moved Permanently or 308 Permanent Redirect for canonical URL restructuring to preserve search engine ranking equity.
  • Rate Limiting (429): Pair 429 Too Many Requests with a Retry-After header in seconds to help well-behaved crawlers back off cleanly.
  • Static Asset Caching (304): Ensure your web server responds with 304 Not Modified on conditional GETs matching the If-None-Match ETag to save bandwidth.
100% Client-Side Privacy Guarantee:All HTTP header parsing, regex analysis, and security scoring execute strictly within your local browser. Zero server endpoints, hostnames, or authentication header tokens are transmitted over networks.
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