How do I exclude users who have already received a particular push notification from a new campaign?

To avoid sending a redundant message, build a segment of users who already received a specific push and use it as an exclusion in your new campaign.

This relies on the PW_NotificationSend default event and its message_id attribute.

Steps to create an exclusion segment:

1. Find the message identifier. Open the message report / statistics for the push whose recipients you want to exclude and copy its message_id. PW_NotificationSend also carries message_code and campaign_id, so you can filter by campaign instead of a single message if that fits better.
2. Create the segment of users who received that push.
   • Go to Audience → Segments and create a new segment.
   • In Add filter by, choose Event and select PW_NotificationSend.
   • Set the occurrence condition, for example exactly or more / 1 time, with a time frame that covers the original send.
   • Click + Attribute, pick message_id, choose the is operator and paste the value from step 1.
3. Exclude the segment. In the new campaign's audience settings, add this segment as an exclusion (a NOT / "exclude segment" condition) so its members are skipped.

Important notes:

• PW_NotificationSend only has data from the moment it was enabled for your project, so this reliably covers pushes sent after activation. For older sends, contact Pushwoosh support.
• PW_NotificationOpen has no documented attributes, so you cannot filter opens by message or campaign id the way you can with PW_NotificationSend. Use PW_NotificationSend with message_id, or build the list from the message report's "Opened" recipients export.
• If your goal is simply to limit overall message volume per user, Global frequency capping (Settings → Message delivery settings → Frequency capping) is a simpler alternative to hand-built exclusions.

See Default events and Build segments by events.