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How to add Referrer-Policy on Cloudflare

Last updated · Reviewed by a CISSP-certified security practitioner

To add Referrer-Policy on Cloudflare, set the header in Rules → Transform Rules → Modify Response Header (or a Worker) with the value strict-origin-when-cross-origin. Limits how much of your URLs leak to other sites. Purge cache, then check the response with curl -I. Then confirm it with curl -I or a free FixSecurityHeaders scan.

What does Referrer-Policy do?

Referrer-Policy controls what URL information the browser sends to other sites when users click links or load resources.

Risk if missing: Full URLs — including reset tokens, search terms or internal paths — can leak to third parties.

What is the Cloudflare configuration?

Add this to Rules → Transform Rules → Modify Response Header (or a Worker):

Rules → Transform Rules → Modify Response Header (or a Worker)
// Option A: Rules → Transform Rules → Modify Response Header → "Set static"
//   Referrer-Policy: strict-origin-when-cross-origin

// Option B: Cloudflare Worker
export default {
  async fetch(request, env, ctx) {
    const res = await fetch(request);
    const out = new Response(res.body, res);
    const h = out.headers;
    h.set("Referrer-Policy", "strict-origin-when-cross-origin");
    return out;
  },
};

How do I add it step by step?

  1. Open Rules → Transform Rules → Modify Response Header (or a Worker).
  2. Paste the Referrer-Policy configuration shown below.
  3. Purge cache, then check the response with curl -I.
  4. Run curl -I https://yourdomain.com and look for the referrer-policy line.
  5. Scan your site on FixSecurityHeaders to confirm the grade improved.

How do I verify it worked?

terminal
curl -sI https://yourdomain.com | grep -i "referrer-policy"
# expected:
# referrer-policy: strict-origin-when-cross-origin

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What are the common mistakes?

  • no-referrer is stricter but can break analytics attribution and some payment flows.
  • Transform Rules work on all plans; Workers give full control.
  • Cloudflare's own HSTS setting lives under SSL/TLS → Edge Certificates.

Quick reference

HeaderReferrer-Policy
Recommended valuestrict-origin-when-cross-origin
StackCloudflare
WhereRules → Transform Rules → Modify Response Header (or a Worker)
ComplianceOWASP ASVS V14.4.6, SOC 2 CC6.7

FAQ

What value should I use for Referrer-Policy?

A safe default is strict-origin-when-cross-origin. no-referrer is stricter but can break analytics attribution and some payment flows.

Why isn't Referrer-Policy showing up on Cloudflare?

Transform Rules work on all plans; Workers give full control. Also clear any CDN or page cache, and check you edited the config that actually serves your domain.

Does Referrer-Policy affect SEO or performance?

No measurable performance cost — it's a few bytes per response. It doesn't affect rankings directly, but a misconfigured policy can break page resources, so test before enforcing.

Which compliance frameworks reference Referrer-Policy?

OWASP ASVS V14.4.6, SOC 2 CC6.7.

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