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© 2026 Oppulence Engineering · Verifier

Integrations/03 of 06/Postmark

Send Postmark events back to your suppression list

Point a Postmark webhook at your workspace. Bounces, spam complaints, and unsubscribes update your suppression list.

Get started freeDelivery feedback
Fig. 1Postmark → Verifier

1.1 Postmark

PostmarkWebhooks

1.2 Delivery endpoint

  • Token in the URL
  • IP allow list, optional
  • Postmark does not sign events

1.3 Recorded as

  • Delivery → deliveredHistory
  • Bounce → bouncedSuppressed
  • SpamComplaint → complainedSuppressed
  • SubscriptionChange → unsubscribedSuppressed
  • Open → openedHistory
  • Click → clickedHistory
POST /v1/inbound/providers/postmark/{endpoint}/{token}
Source
Postmark webhooks
Verification
Private URL token and IP allow list
Suppressed
Bounces, spam complaints, unsubscribes
Setup
One private URL

§ 1

Why it matters

Delivery problems stay inside Postmark

When an event is only recorded in the email platform, the address comes back with the next import.

Close the loop between Postmark and your list checks.

Fig. 2Without and with Verifier
WithoutWith Verifier
  1. ×Without: Bounces and spam complaints stay in Postmark.→✓With Verifier: Each Postmark event must carry your private URL token.
  2. ×Without: Imports from other tools bring the same addresses back.→✓With Verifier: Bounces, spam complaints, and unsubscribes join one list.
  3. ×Without: Suppression lists differ from tool to tool.→✓With Verifier: Every event shows in the address history.

§ 2

How it works

A private URL for each endpoint

Postmark does not sign webhooks. The private URL carries a secret token, and you can limit the endpoint to a list of IP addresses through the API.

  1. 2.1In Verifier, open Outcomes, and add a Postmark endpoint. Copy its private URL.
  2. 2.2In Postmark, open your server, then the message stream, then Webhooks > Add webhook.
  3. 2.3Paste the URL. Select Bounce, Spam Complaint, and Subscription Change.
Fig. 3One bounce from Postmark

Sent by Postmark

{  "RecordType": "Bounce",  "Type": "HardBounce",  "Email": "[email protected]",  "BouncedAt": "2026-10-16T09:12:44Z",  "MessageID": "883953f4-6105-42a2..."}

Verifier · POST /v1/inbound/providers/postmark/{endpoint}/{token}

{  "provider": "postmark",  "accepted": 1,  "duplicates": 0,  "rejected": 0}

GET /v1/suppressions/[email protected]

{  "suppressed": true,  "reason": "bounce",  "source": "postmark"}
Private URL token, with an optional IP allow list · fields trimmed

§ 3

What you get

What you get.

  1. 3.1One suppression listSuppressions from Postmark sit next to invalid results and manual entries.
  2. 3.2Event historySee the delivery events for each address in its history.

Table 3 · Event mapping

Event from the platformRecorded as
Deliverydelivered
Bouncebounced
SpamComplaintcomplained
SubscriptionChange (suppressed)unsubscribed
Openopened
Clickclicked

§ 4

In practice

Typical uses.

  • Case 4.1

    Stop repeat problems

    A suppressed address goes to the drop file when you clean your next list.

  • Case 4.2

    More than one sending tool

    A Postmark bounce also stops the address in lists from your CRM and other tools.

Other integrations.

All integrations
  • SendGrid
  • Mailgun
  • Amazon SES
  • CSV files
  • REST API

Questions

Before you start.

Which events are recorded?

The event mapping on this page shows what is recorded. Bounces, spam complaints, and unsubscribes go on the suppression list.

Which subscription changes are suppressed?

A SubscriptionChange event with SuppressSending set to true is recorded as an unsubscribe. A change that turns sending back on is not.

Continue reading

  1. 01Delivery feedback
  2. 02Suppression list
  3. 03Start free