HTTP Headers Viewer
Inspect HTTP response headers including security and CORS
Enter a web address to begin.
Result
Response headers appear here.
About HTTP Headers Viewer
The HTTP Headers Viewer is a free online tool that lets you inspect every response header returned by any website. HTTP headers are metadata key-value pairs exchanged between a client (your browser or application) and a server during every HTTP request and response cycle. They carry critical information about content type, caching behavior, security policies, server identity, and CORS configuration.
Understanding HTTP response headers is essential for web developers debugging API integrations, SEO specialists auditing crawl behavior, and security engineers hardening web applications. Missing security headers like Content-Security-Policy or Strict-Transport-Security can leave your site vulnerable to XSS, clickjacking, and protocol-downgrade attacks. Misconfigured caching headers can hurt page speed scores and waste bandwidth.
This header checker tool fetches the target URL, captures every response header, groups them by category (content, caching, security, cookies, server, CORS), and displays the results with color-coded labels. Copy individual headers or the full set, or export them as JSON, CSV, or TXT for documentation, bug reports, or configuration files.
Key Features
- Fetch and display all HTTP response headers for any public URL
- Automatic grouping into Content, Caching, Security, Cookies, Server, CORS, and Other categories
- Color-coded category labels for quick visual identification
- One-click copy for individual headers or the entire header set
- Response status code, status text, and response time displayed at a glance
- Quick-test buttons for popular sites like Google, GitHub, and Cloudflare
- Automatic URL normalization (adds https:// if no protocol is provided)
- Dark mode support for comfortable viewing in any environment
- Fully responsive layout that works on desktop, tablet, and mobile
- Export the header list as JSON, CSV, or TXT
How to Use
- Enter a URL: Type or paste the website address you want to inspect into the input field. The tool accepts URLs with or without the https:// prefix.
- Click Get Headers: Press the button or hit Enter to send the request. The tool will fetch the URL and capture all response headers.
- Review grouped results: Headers are automatically organized into categories such as Security, Caching, Content, and CORS so you can find what you need quickly.
- Copy headers: Use the copy icon next to any individual header, or click "Copy All" to copy the full header set to your clipboard.
- Try quick tests: Use the pre-loaded URL buttons for Google, GitHub, or Cloudflare to see example header configurations from major sites.
- Analyze & act: Compare the returned headers against best practices for security, caching, and performance, then update your server configuration accordingly.
Use Cases
- Security auditing: Check whether a website returns essential security headers like Content-Security-Policy, X-Frame-Options, and Strict-Transport-Security.
- Performance optimization: Inspect Cache-Control, ETag, and Expires headers to verify that static assets are being cached correctly for faster page loads.
- CORS debugging: View Access-Control-Allow-Origin and related headers to diagnose cross-origin request failures in your web application.
- API development: Confirm that your API returns the correct Content-Type, status codes, and custom headers before releasing to production.
- SEO analysis: Verify that redirect chains use proper 301/302 status codes and that server response times meet performance benchmarks.
- Competitor research: Discover which web servers, CDNs, and security configurations competitors are using by reading their Server and Via headers.
- Cookie inspection: Review Set-Cookie headers to understand session management, cookie flags (HttpOnly, Secure, SameSite), and expiration policies.
- DevOps monitoring: Quickly spot misconfigured headers on staging or production environments without needing command-line tools like curl.
Frequently Asked Questions
Why are some headers missing?
Some servers strip or omit certain headers depending on the request method, user agent, or geographic location. The tool displays every header present in the actual HTTP response.
Can I check headers for any URL?
You can inspect headers for any publicly accessible URL. Sites behind authentication walls or firewalls may return error codes or limited headers.
What do the category colors mean?
Headers are grouped by function: blue for Content, green for Caching, red for Security, yellow for Cookies, purple for Server info, orange for CORS, and gray for Other uncategorized headers.
Does the tool follow redirects?
Yes. The fetch follows redirects and returns the status code and headers of the final response. The URL shown is the one you entered.
Tips & Best Practices
- Always set security headers: At minimum, configure Content-Security-Policy, Strict-Transport-Security, X-Content-Type-Options, and X-Frame-Options on every production site.
- Leverage caching: Use Cache-Control with appropriate max-age values for static assets and ETags for dynamic content to reduce server load and improve page speed.
- Hide server info: Remove or obfuscate the Server and X-Powered-By headers to avoid revealing your technology stack to potential attackers.
- Configure CORS carefully: Avoid using a wildcard (*) for Access-Control-Allow-Origin in production. Specify exact allowed origins to prevent unauthorized cross-origin access.
- Test after every change: After modifying your server configuration, use this tool to verify that new headers are being sent correctly before deploying to production.
- Compare against benchmarks: Check headers on high-traffic sites like Google and Cloudflare to see industry-standard configurations and adopt similar practices.