Build a DMARC record

Compose the TXT value for _dmarc.<domain> from a policy and an optional report address.

JavaScript Version 1.0.0 · MIT · by Oveyon · .md

function dmarcRecord({ policy, rua }) { return ['v=DMARC1', `p=${policy}`, ...(rua ? [`rua=${rua}`] : [])].join('; '); }

Try in the local lab Download function

Input & expected output

Input

{
  "policy": "none",
  "rua": "mailto:[email protected]"
}

Expected output

"v=DMARC1; p=none; rua=mailto:[email protected]"

The edge case

Input

{
  "policy": "reject"
}

Expected output

"v=DMARC1; p=reject"

Know the limits

Publish the value as a TXT record at _dmarc.<your-domain>; v=DMARC1 must come first (RFC 7489). Start with p=none and aggregate reports, then move to quarantine and reject once SPF or DKIM alignment holds.
Oveyon’s POST /v1/domains returns the SPF, DKIM and DMARC records to publish for a sending domain; prefer those values when they are available.

The function above is the implementation used by the lab. The lab validates JSON types and caps size before execution; include equivalent validation when accepting untrusted input in your application.

Source & maintenance

The function above is the implementation the lab runs and the tests exercise. Read the license.

Local fixture scope · Node.js 22.23.2 · reviewed October 28, 2026. No external service is required.

Keep exploring

Convert an email domain to punycode — Keep the local part and convert an international domain to its ASCII xn-- form.
Get the domain of an email address — Take the part after the last @ and lowercase it, for domain checks and grouping.
Mask an email address for logs — Keep the first character and the domain; hide the rest of the local part.