HSTS checker

About Our HSTS Checker Tool

The HSTS Checker tool helps you verify whether a website has correctly implemented HTTP Strict Transport Security (HSTS) — a critical security feature that ensures browsers only connect to a site through secure HTTPS. HSTS protects users from man-in-the-middle attacks, SSL stripping, and insecure fallback connections. This tool analyzes the website's response headers to determine if HSTS is enabled, properly configured, and optimized for maximum security.

What This Tool Can Detect

Our HSTS Checker scans the website’s HTTP response headers to confirm the presence and configuration of the Strict-Transport-Security directive. It provides detailed insights such as:

• HSTS Status: Detects whether HSTS is enabled or missing.
• Max-Age Value: Shows how long browsers should enforce HTTPS.
• IncludeSubDomains: Checks if HSTS applies to all subdomains.
• Preload Flag: Indicates whether the site is eligible for HSTS preload lists.
• Security Header Quality: Evaluates the completeness of the HSTS configuration.
• HTTPS Enforcement: Confirms if the website correctly redirects HTTP to HTTPS.

Why HSTS Matters

HSTS is a powerful web security policy used to enforce encrypted connections and prevent security risks. Without HSTS, browsers may attempt insecure HTTP requests, leaving users vulnerable to attacks. Proper HSTS implementation is essential for security-focused websites, eCommerce platforms, and any site handling sensitive data.

• Prevents SSL stripping attacks.
• Forces browsers to load only the HTTPS version of your website.
• Improves site security trustworthiness.
• Helps websites qualify for HSTS preload lists.
• Strengthens overall SSL/TLS protection.

Common Issues This Tool Helps Detect

The HSTS Checker helps uncover serious configuration and security risks such as:

• Missing or incorrect Strict-Transport-Security header.
• HSTS enabled but with too low max-age value.
• Missing includeSubDomains flag, causing partial protection.
• Preload flag missing for sites wanting Google Chrome preload inclusion.
• HTTP to HTTPS redirects misconfigured or inconsistent.
• HSTS applied on non-HTTPS endpoints (invalid configuration).

How HSTS Checking Works

When you enter a URL, the tool sends an HTTPS request and reads the server’s response headers. It extracts the HSTS header (if it exists) and analyzes its directives. Based on this, the tool determines the security level, flags missing configurations, and provides a clear overview of your website’s HTTPS enforcement and HSTS readiness.

Advanced Insights

Security professionals use this tool to validate SSL/TLS best practices, evaluate production environments, diagnose HTTPS migration issues, and ensure compliance with industry standards. HSTS is especially important for websites seeking maximum browser protection and inclusion in global preload lists.

Final Notes

The HSTS Checker is essential for ensuring your website enforces secure connections and protects users from cyber threats. Whether you're managing a high-security website, performing a technical audit, or preparing for HTTPS migration, this tool gives you clear and accurate insights into your HSTS configuration.