Where do I publish the DKIM record for Postmark?

You publish DKIM as a TXT record at selector._domainkey.yourdomain.com, where selector is the name given by Postmark.

How do I know if DKIM is working?

Send a message to a Gmail inbox and look at Show original. If DKIM shows PASS for your domain, the record is working.

Yes. Many providers support multiple selectors to rotate keys or support several sending systems.

Step by step DKIM setup for Postmark: complete instructions, examples, verification commands, and common pitfalls.

Want to check your domain while following this guide?

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This is a reference guide for configuring DKIM on Postmark. Use it while editing DNS or when troubleshooting deliverability.

Tip: Avoid common mistakes: follow these steps to add DKIM on Postmark. Then verify everything with the InboxGreen Free Checker.

Postmark uses Sender Signatures, not domain-level DKIM by default. Each sender signature domain gets its own DKIM record published by Postmark.
Postmark DKIM keys rotate periodically. If DKIM suddenly fails, check the Postmark dashboard for an updated record value.
Postmark → Sender Signatures → Domain → DKIM.

In Postmark, generate a DKIM key and note the selector. Providers often suggest something like pm (Postmark generates the selector per domain).

Postmark → Sender Signatures → Domain → DKIM.

Create a TXT record at host selector._domainkey (replace selector with your actual selector name).
Paste the full value starting with v=DKIM1; k=rsa; p= and save.
Wait for DNS propagation.

Send a test email to a Gmail address and use “Show original” to confirm “DKIM: PASS”.

Or run:

dig TXT selector._domainkey.yourdomain.com +short

Using the wrong host so the record becomes selector._domainkey.yourdomain.com.yourdomain.com.
Breaking the value by wrapping or truncating the TXT string.
Publishing a record for the wrong selector and then validating on another.

Check SPF, DKIM, DMARC and List-Unsubscribe for your domain in seconds.