Security Headers Every Website Should Implement in 2026

/Essential Security Headers

HTTP security headers instruct browsers on how to handle your content, preventing a wide range of client-side attacks. Despite being easy to implement, many websites still miss critical headers.

/Content-Security-Policy (CSP)

CSP is the most powerful header for preventing XSS attacks. It controls which resources the browser is allowed to load. A strong CSP policy blocks inline scripts, restricts resource origins, and reports violations.

Content-Security-Policy: default-src 'self'; script-src 'self'; style-src 'self' 'unsafe-inline'; img-src 'self' data: blob: https:; font-src 'self'; connect-src 'self'; frame-ancestors 'none'; base-uri 'self'; form-action 'self'; object-src 'none'

/Strict-Transport-Security (HSTS)

HSTS forces browsers to only connect via HTTPS, preventing protocol downgrade attacks and cookie hijacking. For production, use a minimum of 2 years with includeSubDomains and preload.

Strict-Transport-Security: max-age=63072000; includeSubDomains; preload

/Complete Header Checklist

• Content-Security-Policy: Controls resource loading
• Strict-Transport-Security: Enforces HTTPS
• X-Content-Type-Options: nosniff - Prevents MIME sniffing
• X-Frame-Options: DENY - Prevents clickjacking
• Referrer-Policy: Controls referrer information
• Permissions-Policy: Restricts browser features
• Cross-Origin-Opener-Policy: same-origin - Prevents cross-origin attacks
• Cross-Origin-Resource-Policy: same-origin - Prevents resource theft

Our security scanner evaluates all of these headers and more. Run a free assessment to see your current security posture and receive specific recommendations for your infrastructure.