Security Headers Checker Tool Online

How the Security Headers Checker Works

This tool inspects the HTTP response headers that a web server sends to browsers. Here's the process:

1. Enter a URL, type or paste any website address. The tool sends an HTTP HEAD request to retrieve only the headers (no page content is downloaded).
2. Header inspection, it checks for 10 critical security headers recommended by OWASP and major browser vendors.
3. Evaluation, each header is evaluated: present or missing, properly configured or suboptimal, with specific recommendations for improvement.
4. Summary, results show a pass/warn/fail breakdown with color-coded status for quick assessment.

Why Security Headers Matter

Security headers are your website's first line of defense. They cost nothing to implement and protect against the most common web attacks:

• XSS prevention, Content-Security-Policy controls which scripts can execute on your page. Without it, attackers can inject malicious JavaScript through comments, form fields, or compromised third-party resources.
• Clickjacking protection, X-Frame-Options and CSP frame-ancestors prevent your site from being embedded in a hidden iframe on an attacker's page, where users might unknowingly click on your site's buttons.
• HTTPS enforcement, HSTS ensures browsers always use HTTPS, eliminating the window of vulnerability during the first HTTP request. This protects against man-in-the-middle attacks on public Wi-Fi.
• Data leak prevention, Referrer-Policy controls what URL information is sent to third-party sites. Without it, sensitive query parameters can leak to external services.
• Browser feature control, Permissions-Policy lets you disable browser features (camera, mic, geolocation) that your site doesn't need, reducing your attack surface.

Combine this with the SSL Certificate Checker for a complete security profile, the Redirect Checker to verify HTTPS redirects are properly configured, and the Email Deliverability Checker to verify SPF/DKIM/DMARC for your domain, email security and web security go hand in hand. Also run the PHP Version Checker to ensure your server isn't running an end-of-life PHP version, which is a common source of security vulnerabilities.

Essential Security Headers to Implement

If you're starting from scratch, prioritize these headers in order:

• Strict-Transport-Security, max-age=31536000; includeSubDomains, enforces HTTPS for 1 year across all subdomains.
• Content-Security-Policy, start with default-src 'self' and add sources as needed. This single header addresses the widest range of attack vectors.
• X-Content-Type-Options, nosniff, one word, zero risk, prevents MIME sniffing attacks.
• X-Frame-Options, DENY or SAMEORIGIN, prevents clickjacking. Takes 30 seconds to add.
• Referrer-Policy, strict-origin-when-cross-origin, sensible default that shares origin but not path to third parties.
• Permissions-Policy, disable features you don't use: camera=(), microphone=(), geolocation=()

For a broader website audit, check your meta tags, schema markup, and broken links alongside security headers for a complete health check.

Key HTTP Security Headers and Recommended Values

Use this reference to understand what each core security header does and a sensible value to start with. Adjust the exact directives to fit your site, but these defaults are a safe, widely recommended baseline.