Send email through your own Postmark account

You will need a Postmark account and access to your domain's DNS.

Postmark's own documentation: Sender signatures and domains · Server API tokens · Sign up

⭐ Why we would pick Postmark for this. It refuses to carry marketing email at all, which is exactly why its delivery rates are what they are: your invoices are not sharing a reputation with somebody else's newsletter. If your only requirement is that transactional mail arrives, this is the one.

1. Add and verify your domain

Sender Signatures → Domains → Add Domain, and enter a subdomain such as mail.yourdomain.com.

Postmark gives you two records:

Add both, then press Verify.

⭐ Add the return-path record, even though Postmark marks it optional. Without it your messages are sent with Postmark's own bounce domain, so SPF aligns to postmarkapp.com rather than to you. DKIM alone will still get you a DMARC pass — but you have thrown away one of the two checks for no reason, and you will want both the first time a large receiver gets strict.

⚠️ Postmark does not require an SPF record because it does not use your domain as the envelope sender. If you already have SPF, leave it alone.

2. Get your Server API token

Open the server you want to send from — Postmark calls a sending environment a "server" — then API Tokens, and copy the Server API token.

⛔ The Server token, not the Account token. The Account token manages your whole Postmark account: it can create servers, change domains and read every message you have ever sent. The Server token can send from one server. They look alike and are pasted into the same kind of box, and this is the single easiest mistake to make on this page.

⭐ Consider creating a separate server for this — call it "Zinn® notifications". Postmark's statistics, bounce lists and activity feed are all per-server, so a separate one means your client notifications are not mixed in with anything else you send.

3. Connect it in Zinn®

Open Email sending in your dashboard:

• Provider — Postmark
• Send from this domain — mail.yourdomain.com
• Message stream — leave as outbound unless you have created your own
• Postmark server token — the token from step 2

⚠️ Message stream must be a transactional stream. Postmark rejects transactional-looking mail sent on a broadcast stream, and password resets and invoices are transactional.

4. Send the test and enter the code

Press Send test message to an inbox on a different domain, read the code out of it, and enter it.

When it does not work

"You tried to send to a recipient that has been marked as inactive" — Postmark suppresses an address after a hard bounce or a spam complaint, permanently, until you reactivate it. Look in Suppressions. This is Postmark protecting you, and it is usually right.

422 with "Invalid 'From' address" — the domain in Send from this domain is not verified in Postmark, or you verified yourdomain.com and are sending from mail.yourdomain.com. Postmark matches the exact domain.

401 Unauthorized — you pasted the Account token instead of the Server token (see above), or the token belongs to a different server.

Everything works but it is in the spam folder — check that DKIM shows Verified in Postmark and that your DMARC record is not set to p=reject while something else about your domain is still misaligned.