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Free HTTP Header Checker
& Security Headers Analyzer

Check HTTP response headers, analyze security headers with grading, verify Last-Modified dates, and detect cache policies. No signup required.

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The Best Free HTTP Header Checker Online

More comprehensive than securityheaders.com. Check HTTP headers, get security grading, analyze Last-Modified dates, and more.

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Security Headers Grading

Get an A+ to F grade for your security headers. Check CSP, HSTS, X-Frame-Options, X-XSS-Protection, and more.

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Last-Modified Detection

Check when content was last updated. Important for SEO and cache validation. See exact timestamps and freshness.

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All Headers Analysis

See every HTTP header with explanations. Content-Type, Cache-Control, Server, CORS headers, and all custom headers.

Essential Security Headers Explained

Critical

Content-Security-Policy (CSP)

Prevents XSS attacks by specifying which sources of content are allowed. The most important security header for modern websites.

Critical

Strict-Transport-Security (HSTS)

Forces browsers to use HTTPS. Prevents downgrade attacks and cookie hijacking. Should include max-age and preload directive.

Important

X-Frame-Options

Prevents clickjacking attacks by controlling whether your site can be embedded in iframes. Use DENY or SAMEORIGIN.

Important

X-Content-Type-Options

Prevents MIME type sniffing attacks. Set to "nosniff" to ensure browsers respect the declared Content-Type.

Recommended

Referrer-Policy

Controls how much referrer information is shared when navigating away. Protects user privacy and prevents information leakage.

Recommended

Permissions-Policy

Controls which browser features can be used. Restrict access to camera, microphone, geolocation, and other sensitive APIs.

HTTP Header Checker FAQ

What HTTP headers should I check for SEO? expand_more
For SEO, check these headers: Last-Modified (content freshness), Cache-Control (caching behavior), Content-Type (proper MIME type), X-Robots-Tag (indexing directives), and Canonical link headers. These affect how search engines crawl and index your content.
How do I improve my security headers grade? expand_more
Add these headers to your server configuration: 1) Strict-Transport-Security with max-age, 2) Content-Security-Policy restricting sources, 3) X-Frame-Options: DENY, 4) X-Content-Type-Options: nosniff, 5) Referrer-Policy: strict-origin-when-cross-origin. Most web servers support adding these via config files.
What does the Last-Modified header tell me? expand_more
The Last-Modified header shows when the content was last changed on the server. Browsers use this for conditional requests (If-Modified-Since). Search engines use it to understand content freshness. If missing, browsers can't efficiently cache content, and search engines may assume content is stale.
How do I check HTTP headers in Chrome? expand_more
In Chrome: Open DevTools (F12), go to Network tab, reload the page, click on a request, and view Response Headers. However, our tool is faster and provides security grading, Last-Modified analysis, and explanations that DevTools doesn't offer.
Is this better than securityheaders.com? expand_more
Our HTTP header checker offers unique features: security grading plus all HTTP headers display, Last-Modified analysis for SEO, integration with our HTTP status checker and DNS tools, modern interface, and no annoying popups. We're the only tool that combines security analysis with SEO-relevant header checking.

Need More Testing Tools?

Check HTTP status codes, DNS propagation, and headers all in one platform. The complete toolkit for developers and SEO professionals.

Enterprise

Need Bulk Security Header Auditing?

Scan thousands of URLs for security headers, content security policies, and HTTP header configurations. Perfect for security teams, compliance audits, and enterprise deployments.

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