HTTP Observatory VS PlugLeak

Overall verdict

• HTTP Observatory by Mozilla (now hosted on MDN) is a free, reliable, and well-maintained security scanning tool that helps developers assess and improve the security posture of their websites through actionable, standards-based recommendations.

Why this product is good

• It's completely free to use and backed by Mozilla, a trusted name in web standards and security
• Provides a clear letter-grade score along with detailed, actionable feedback on HTTP security headers
• Checks important security configurations like Content Security Policy (CSP), HSTS, X-Frame-Options, cookies, and more
• Offers educational context and links to MDN documentation, helping developers understand the 'why' behind each recommendation
• Continuously updated to reflect current web security best practices
• Simple, straightforward interface that requires no signup or installation to run a basic scan

Recommended for

• Web developers looking to harden the security of their sites
• Security engineers performing quick baseline assessments of HTTP headers
• Small teams or solo developers without a dedicated security budget
• Educators and students learning about web security best practices
• DevOps professionals integrating security checks into their workflows
• Anyone wanting to validate their site's security headers against modern standards