Make Postmark DMARC-compliant
How to authenticate Postmark as a sender on your domain - so its mail passes SPF, DKIM and DMARC, and you can safely reach enforcement.
Three steps to authenticate Postmark
Postmark needs to pass SPF and DKIM, and align with your domain so DMARC passes. Here’s how – confirm the exact values against Postmark’s current documentation as you go.
Add Postmark to your SPF record
SPF lists the services allowed to send as your domain. Add Postmark’s include to your existing SPF record – don’t create a second SPF record, merge it into the one you have.
Watch the 10-lookup limit: every include counts, and going over makes SPF fail silently. Hosted SPF keeps you safely under it automatically.
Add this mechanism to your SPF record
include:spf.mtasv.net
Turn on DKIM signing
DKIM cryptographically signs each message so receivers can prove it really came from you and wasn’t tampered with. Add your domain / Sender Signature in Postmark and publish the DKIM TXT record it provides.
DKIM is what keeps you authenticated even when a message is forwarded – so it’s worth getting right. More on how DKIM works →
- Enable DKIM inside Postmark
- Publish the DNS records it gives you
- Wait for it to verify, then send a test
Confirm alignment, then enforce
With SPF and DKIM set up, check that Postmark aligns – that the authenticated domain matches your visible From address. Once every legitimate sender aligns, you can move DMARC to p=reject safely.
DMARCER’s enforcement journey shows you exactly when it’s safe to advance – no guesswork.
Good to know
Postmark also offers a Return-Path CNAME for full alignment - publish it if you want SPF to align too.
Check you got it right
Look up your records instantly, or run a full free check to confirm Postmark passes SPF, DKIM and DMARC – and get your score out of 100.
Check SPF Full free check