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Monitoring Postmark Bounces

This JSON sensor monitors the number of soft bounces returned by the Postmark API and triggers an alert when the count exceeds a defined threshold.

Purpose

Use this sensor to ensure that the number of soft bounces in your transactional email delivery remains below a healthy limit. This is useful for identifying delivery issues early and maintaining email reputation.

Use Case Example

If your application sends transactional emails (e.g., password resets, order confirmations), you want to be informed if emails start bouncing. A sudden increase in soft bounces may indicate temporary delivery problems (e.g., full inboxes, DNS issues, rate-limiting) and could degrade your deliverability if left unchecked.

Configuration Overview

Field Value
Verb GET
URL https://api.postmarkapp.com/deliverystats
JsonPath $.Bounces[?(@.Type == 'SoftBounce')].Count
Condition Less than
Check value type Int
Value to check 10
Recursion 15 min
Timeout 15000 ms
HTTP codes accepted 2xx
Auth type None
Headers
- Accept application/json
- X-Postmark-Server-Token 6a14a4d3-2c80-4b83-a7f0-e9f57cffe0e5

💡 Note: Replace the Postmark server token with your own private token. Avoid sharing it publicly.

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Explanation of Key Fields

  • JsonPath: The expression filters the list of bounces returned by Postmark, selecting only entries of type "SoftBounce", and retrieves their count.
  • Condition: An alert will be triggered if the count is less than 10. This can be adjusted depending on your tolerance threshold.
  • Recursion (Check frequency): The sensor performs this check every 15 minutes.
  • Timeout: The HTTP request will time out after 15 seconds if no response is received.
  • Accepted HTTP Codes: The response must return a code in the 2xx ranges to be considered valid.
  • Headers: The Postmark API requires an API token provided via the custom header X-Postmark-Server-Token.

Good Practices

  • Rotate and secure your Postmark API tokens regularly.
  • Combine this sensor with other mail delivery metrics (e.g., hard bounces, spam complaints).
  • Consider setting a higher frequency or lower threshold in production environments for faster alerting.

To Go Further

This official documentation page provides detailed information about how to retrieve, filter, and interpret bounce data using Postmark’s API.