How can I create a Journey that sends a push notification, with a fallback to an in-app message for users who have pushes disabled?

You can build a push-first flow with an in-app fallback using the Reachability check flow-control element in Customer Journey.

Recommended Journey flow

1. Entry element — start the Journey with a trigger-based, audience-based or API-based entry.

2. Add a "Reachability check" element and select the Push notifications channel.

   • The element reviews the Push alerts enabled tag and splits users into two branches: those with the tag set to true and those with false.
   • Reachable branch → add a Push element to send the notification.
   • Not-reachable branch → add an In-app element as the fallback.

3. Finish each branch with an "Exit" element so users leave the Journey cleanly.

Example Journey structure

• Entry element
  • Reachability check: Push notifications
    • Reachable → Push → Exit
    • Not reachable → In-app → Exit

Notes

• There is no separate "Filter" element in Customer Journey. If you need to branch on segments or tag values, use the Condition split element (previously called "Segment split").
• Reachability check is not a device-existence check: it evaluates the Push alerts enabled tag. User profiles that were imported and never registered a device simply have no push-reachable device and follow the not-reachable branch.
• You can chain Reachability checks (for example, follow the push not-reachable branch with a Reachability check for Email) to cover more channels.

See Reachability check in the documentation.