What are HTTP Headers?

HTTP headers are key-value pairs sent between a client (browser) and a server. They contain meta-data about the request or response, such as content type, caching policies, and security settings.

Why is CORS blocking my request?

Browsers enforce Same-Origin Policy. If a website doesn't explicitly allow external tools to read its headers (via Access-Control-Allow-Origin), the browser blocks the data. This tool works best on APIs or sites that enable CORS.

Http Header Checker Online

Why Check HTTP Headers?

HTTP headers carry vital information about the connection between a browser and a server. They control caching, content encoding, and critical security policies. Misconfigured headers can lead to security vulnerabilities or poor website performance.

Important Security Headers

Strict-Transport-Security (HSTS): Forces browsers to load your site over HTTPS only, preventing protocol downgrade attacks.
Content-Security-Policy (CSP): Helps prevent Cross-Site Scripting (XSS) and data injection attacks by restricting the sources of executable scripts.
X-Frame-Options: Prevents your site from being embedded in iframes on other sites, protecting against Clickjacking.

Performance Headers

Cache-Control

Directs the browser on how long to cache the page assets. Proper configuration speeds up load times for returning visitors.

Content-Encoding

Indicates compression methods (like Gzip or Brotli). Compressed content transfers faster over the network.

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Frequently Asked Questions

Everything you need to know about using this free online tool.

HTTP response headers are metadata transmitted by a web server to your browser describing the requested page, caching directives, server software, and security policies like CSP, HSTS, and X-Frame-Options.

Auditing security headers ensures your site is protected against clickjacking, cross-site scripting (XSS), MIME-type sniffing, and insecure transport vulnerabilities.

Yes! All tools on Digital Daptos are completely free forever. There are no usage limits, hidden fees, paywalls, or mandatory account registrations.

100% yes. Calculations, text manipulations, QR codes, and conversions are processed entirely client-side inside your browser via JavaScript. Your data never leaves your device and is not saved to any server.

Yes. All outputs, files, calculations, and generated media are completely royalty-free and unrestricted for personal, commercial, client, and enterprise use.

Yes. Our tools are built mobile-first and work seamlessly across iPhone, iPad, Android smartphones, tablets, macOS, Windows, and Linux devices.

No installation is required. Everything runs instantly in any modern web browser (Chrome, Safari, Firefox, Edge, Brave, etc.) without plugins.

Absolutely! Digital Daptos builds custom calculators, web portals, SaaS platforms, and mobile apps for businesses globally. Contact us via WhatsApp for a direct consultation.

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Free HTTP Header Checker

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Security Header Analysis