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How to add Cross-Origin-Embedder-Policy on Nginx

Last updated · Reviewed by a CISSP-certified security practitioner

To add Cross-Origin-Embedder-Policy on Nginx, set the header in nginx.conf (server block) with the value require-corp. Requires embedded resources to opt in (enables cross-origin isolation). Run nginx -t, then systemctl reload nginx. Then confirm it with curl -I or a free FixSecurityHeaders scan.

What does Cross-Origin-Embedder-Policy do?

COEP makes the page refuse cross-origin resources that haven't opted in via CORP or CORS. Combined with COOP it enables cross-origin isolation.

Risk if missing: Informational: mainly needed for SharedArrayBuffer and high-precision timers.

What is the Nginx configuration?

Add this to nginx.conf (server block):

nginx.conf (server block)
# Inside your server { } block
add_header Cross-Origin-Embedder-Policy "require-corp" always;

How do I add it step by step?

  1. Open nginx.conf (server block).
  2. Paste the Cross-Origin-Embedder-Policy configuration shown below.
  3. Run nginx -t, then systemctl reload nginx.
  4. Run curl -I https://yourdomain.com and look for the cross-origin-embedder-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 "cross-origin-embedder-policy"
# expected:
# cross-origin-embedder-policy: require-corp

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What are the common mistakes?

  • Easily breaks third‑party images, fonts and embeds. Consider credentialless, and only deploy if you need isolation.
  • Always add the always flag so headers are sent on error responses too.
  • add_header in a location block replaces all add_header directives inherited from server — repeat them or use an include file.

Quick reference

HeaderCross-Origin-Embedder-Policy
Recommended valuerequire-corp
StackNginx
Wherenginx.conf (server block)
ComplianceOWASP ASVS V14.4

FAQ

What value should I use for Cross-Origin-Embedder-Policy?

A safe default is require-corp. Easily breaks third‑party images, fonts and embeds. Consider credentialless, and only deploy if you need isolation.

Why isn't Cross-Origin-Embedder-Policy showing up on Nginx?

Always add the always flag so headers are sent on error responses too. Also clear any CDN or page cache, and check you edited the config that actually serves your domain.

Does Cross-Origin-Embedder-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 Cross-Origin-Embedder-Policy?

OWASP ASVS V14.4.

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