HTTP Header Analyzer — Understand Every Response Header Instantly
Plain-English explanations, security badges, and missing header warnings
When a deployment breaks caching, a CORS error blocks your API calls, or a security scanner flags your site, the answer is always in the HTTP headers — but decoding dozens of raw header lines is tedious. This analyzer takes raw HTTP response headers (copied from Chrome DevTools, Firefox, curl, or Postman) and transforms them into a readable table. Each header is explained in plain English, tagged with a category (security, caching, content, connection, or CORS), and security-relevant headers get a shield badge. If your response is missing critical headers like Strict-Transport-Security, Content-Security-Policy, X-Frame-Options, X-Content-Type-Options, or Referrer-Policy, a warning panel lists exactly which ones are absent and why they matter.
How to Analyze HTTP Response Headers
Copy your headers from DevTools or curl, paste them in, and get an instant security and caching report.
Get your raw headers
In Chrome: open DevTools (F12), go to the Network tab, reload your page, click the main document request, then click the Headers tab and scroll to Response Headers. Select all the header text and copy it. Alternatively, run curl -I https://yourdomain.com in your terminal to fetch just the headers. Paste the raw output directly into the textarea.
Read the annotated header table
Each parsed header appears in a table row with its name, value, a color-coded category badge (Security, Caching, Content, Connection, or CORS), and a plain-English explanation of what it controls and why it matters. Headers flagged as security-relevant display a shield icon.
Fix missing security headers
The Missing Security Headers panel lists any of the five critical security headers absent from your response: Strict-Transport-Security, Content-Security-Policy, X-Frame-Options, X-Content-Type-Options, and Referrer-Policy. Each missing header links to documentation explaining how to add it to your web server, CDN (Cloudflare, Fastly), or application framework.
Features
Parses any raw HTTP response header block instantly
Plain-English explanation for 30+ common headers
Color-coded category badges: Security, Caching, Content, Connection, CORS
Shield icon on all security-relevant headers
Missing header warning panel for HSTS, CSP, X-Frame-Options, and more
Sample headers included for quick demo
No API call — all parsing runs in your browser
Works with headers from nginx, Apache, Cloudflare, Express, and any HTTP server
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Frequently Asked Questions
What security headers should every website have?
At minimum your server should send five headers: Strict-Transport-Security (HSTS) to enforce HTTPS, Content-Security-Policy (CSP) to prevent XSS, X-Frame-Options to prevent clickjacking, X-Content-Type-Options: nosniff to block MIME sniffing, and Referrer-Policy to control what URL information is sent with requests. Permissions-Policy (formerly Feature-Policy) is also increasingly expected.
How do I get HTTP headers from Chrome DevTools?
Open DevTools with F12, click the Network tab, reload your page, click the document request at the top of the request list, then click the Headers tab. Scroll to the Response Headers section. You can right-click the request and select Copy > Copy response headers to get them all at once.
What does the Cache-Control header do?
Cache-Control directives tell browsers and CDNs how long to cache a response. Common values include max-age=3600 (cache for 1 hour), no-cache (revalidate with the server before using cached copy), no-store (never cache, useful for sensitive pages), and public vs private (whether CDNs are allowed to cache the response).
Why is X-Powered-By a security risk?
X-Powered-By reveals your technology stack — for example X-Powered-By: Express or X-Powered-By: PHP/8.1. This information can help attackers target known vulnerabilities in specific framework versions. Best practice is to remove this header entirely. In Express: app.disable(powered by). In PHP: expose_php = Off in php.ini.
What is the difference between CORS headers and security headers?
CORS headers (Access-Control-Allow-Origin, Access-Control-Allow-Methods, etc.) control which origins can make cross-origin requests to your API — a browser-enforced permission system. Security headers (CSP, X-Frame-Options, HSTS) protect against specific attack classes like XSS, clickjacking, and protocol downgrade. Both are important but serve distinct purposes.