Paste raw response headers from DevTools, curl -I, or a server config output.
Ready to audit
Paste HTTP headers and check your security posture// audit HTTP security headers from pasted responses
Check HTTP security headers from pasted response headers, find missing protections, score risk, and copy safer header recommendations.
Ready to audit
Paste HTTP headers and check your security postureCopy a raw response header block from browser DevTools, curl, or your hosting panel.
The tool detects missing, weak, and recommended HTTP security headers.
Review the generated starter headers and adapt them to your app before deployment.
Security Headers Checker reviews pasted HTTP response headers for browser protections such as HSTS, CSP, frame blocking, MIME sniffing prevention, permissions control, and privacy-focused referrer behavior.
No. This version checks pasted headers only, so it runs locally in your browser and does not make network requests.
No. Security headers are only one layer. You still need secure code, TLS, authentication, access control, dependency updates, and monitoring.
CSP depends heavily on your site. The checker flags obviously weak values, but you should test CSP carefully before enforcing it.
Only after you are certain every subdomain supports HTTPS. Preload can be difficult to undo and should be deployed carefully.
HSTS, CSP, X-Content-Type-Options, frame protection, Referrer-Policy, and Permissions-Policy are common high-impact headers.
Use them as a starting point. Adjust CSP, Permissions-Policy, and cross-origin policies for your app, assets, and integrations.
A security headers checker is a developer utility that reviews HTTP response headers and points out browser-level protections that are missing, weak, or worth improving. Modern browsers support many defense mechanisms that are controlled by response headers. These headers can reduce the impact of cross-site scripting, clickjacking, MIME sniffing, insecure transport, over-shared referrer data, and unnecessary access to powerful browser features.
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This tool focuses on pasted response headers rather than live crawling. That makes it useful when you are working with local servers, staging environments behind authentication, copied curl output, hosting dashboard snippets, or deployment logs. Paste the raw header block, click the check button, and the page will parse each header name and value in the browser.
The checker reviews common production headers including Strict-Transport-Security, Content-Security-Policy, X-Frame-Options, X-Content-Type-Options, Referrer-Policy, Permissions-Policy, Cross-Origin-Opener-Policy, and Cross-Origin-Resource-Policy. It also detects legacy or less preferred headers such as X-XSS-Protection. These checks are designed to be practical and readable rather than overly noisy.
Strict-Transport-Security, often called HSTS, tells browsers to prefer HTTPS for future visits. A strong HSTS value usually includes a long max-age and may include subdomain coverage. Content-Security-Policy controls which scripts, styles, frames, images, and other resources can load. A strict CSP can greatly reduce the blast radius of injection bugs, but it must be customized to your application. X-Content-Type-Options with nosniff helps prevent browsers from interpreting files as a different type than intended.
The score is a fast summary, not a final verdict. A website can have all recommended headers and still contain serious vulnerabilities. A website can also intentionally omit a header because of compatibility needs. Treat the report as a checklist for review. Missing high-impact headers should be investigated first, then weaker values can be tuned based on your framework, hosting provider, and application architecture.
The recommended starter headers are intentionally conservative. They are meant to show a safe direction, but they are not universal. For example, a Content-Security-Policy that works for a static documentation site may break a SaaS dashboard with analytics, inline scripts, third-party widgets, or embedded payment flows. Always test changes in report-only mode or staging before enforcement.
Security headers are valuable because they move part of your defense into the browser. They can block entire classes of risky behavior even when a template, plugin, or dependency makes a mistake. Frame restrictions help prevent clickjacking. Referrer rules reduce accidental leakage of full URLs. Permissions policies limit access to APIs such as camera, microphone, geolocation, and payment features. Cross-origin policies can isolate pages from certain classes of cross-window or resource interaction.
These protections are especially important for admin panels, account pages, checkout flows, API dashboards, and any website that handles user data. They are also useful for static sites because they establish safer defaults and reduce surprises when future scripts or embeds are added.
A quick header check during every launch can catch regressions caused by CDN changes, server migrations, new framework middleware, or reverse proxy rewrites. Copy the report into your deployment notes and keep a known-good header baseline for each important environment.