Headers

Security headers are a low-cost way to harden your site at the edge.

Start with a safe baseline#

Use these headers for all routes (example for Netlify):

[[headers]]
  for = "/*"
  [headers.values]
    Strict-Transport-Security = "max-age=31536000; includeSubDomains; preload"
    X-Content-Type-Options = "nosniff"
    X-Frame-Options = "SAMEORIGIN"
    Referrer-Policy = "strict-origin"
    Permissions-Policy = "geolocation=(self), microphone=(), camera=()"

Add CSP separately and keep it strict#

Treat CSP as its own policy and iterate carefully as scripts and integrations evolve.

• Start with default-src 'self'
• Add only required origins
• Prefer nonces/hashes over unsafe-inline

Be intentional with cache headers#

Apply long-lived caching to fingerprinted static assets, and shorter/revalidated caching to HTML.

Validate after deployment#

In browser dev tools and scanners, confirm:

• Headers are present on HTML and static assets
• HTTPS and HSTS are active
• No unexpected framing or MIME issues
• No CSP violations on critical pages

Related#

• Content Security Policy
• Caching
• Verification