Best Practices and Recommendations

2 min read Web Security Fundamentals

Best Practices and Recommendations

  1. Default Deny Approach: Start with restrictive policies and allow features only where needed
  2. Principle of Least Privilege: Grant minimum necessary permissions for functionality
  3. Regular Audits: Periodically review which features are actually used
  4. Document Feature Usage: Maintain clear documentation of why features are allowed
  5. Test Across Browsers: Ensure compatibility as browser support varies
  6. Consider User Privacy: Respect user preferences and privacy settings
  7. Monitor Policy Violations: Log and analyze permission denials
  8. Gradual Rollout: Test policies thoroughly before full deployment

Permissions-Policy provides powerful control over browser features, significantly reducing attack surface and protecting user privacy. By carefully managing which APIs and capabilities your application can access, you create a more secure and privacy-respecting web experience. As browsers continue to add new capabilities, maintaining proper permissions policies becomes increasingly important for both security and compliance.## Cross-Origin Resource Sharing (CORS) Headers Explained

Cross-Origin Resource Sharing (CORS) represents one of the most misunderstood yet critical aspects of web security. While not traditionally categorized as a security header in the same vein as CSP or HSTS, CORS headers play a fundamental role in protecting resources from unauthorized cross-origin access. Understanding CORS mechanics, proper implementation, and security implications is essential for building secure modern web applications that safely interact across domain boundaries.