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How to add Referrer-Policy on Express / Node

Last updated · Reviewed by a CISSP-certified security practitioner

To add Referrer-Policy on Express / Node, set the header in app.js (helmet) with the value strict-origin-when-cross-origin. Limits how much of your URLs leak to other sites. Restart the Node process and curl -I your app. 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 Express / Node configuration?

Add this to app.js (helmet):

app.js (helmet)
// npm i helmet
const helmet = require("helmet");

app.disable("x-powered-by");
app.use(helmet()); // sensible defaults

// Exact values recommended by FixSecurityHeaders:
app.use((req, res, next) => {
    res.setHeader("Referrer-Policy", "strict-origin-when-cross-origin");
  next();
});

How do I add it step by step?

  1. Open app.js (helmet).
  2. Paste the Referrer-Policy configuration shown below.
  3. Restart the Node process and curl -I your app.
  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.
  • Install with npm i helmet.
  • Call app.use(helmet(...)) before your routes.

Quick reference

HeaderReferrer-Policy
Recommended valuestrict-origin-when-cross-origin
StackExpress / Node
Whereapp.js (helmet)
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 Express / Node?

Install with npm i helmet. 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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