How does the 'Reachability check' element work in Customer Journeys?

The element is called Reachability check in the Customer Journey builder (older material may call it "Reachable by Push"). It splits the flow into two branches depending on whether the traveller can currently be reached over the channel you select.

Channels it can check: Push, Email, SMS, WhatsApp and LINE — not push only. You pick the channel when configuring the element.

How the check is made:

• For push, Pushwoosh looks at the subscription state of the traveller's device(s) — the Push Alerts Enabled tag / presence of a valid, active push token. Users with a subscribed, push-capable device go down the "reachable" branch.
• For email, users whose Unsubscribed Email tag is true (or who have no valid email registered) go down the "not reachable" branch. SMS, WhatsApp and LINE work the same way against their own registered identifiers.

Things to keep in mind:

• The check reflects the state at the moment the traveller reaches the element. If the app was uninstalled or notifications were disabled after the user entered the journey, the traveller can be routed as unreachable.
• Web push subscriptions are push subscriptions too — a web subscriber with a valid token is push-reachable.
• Use the "not reachable" branch to fall back to another channel (for example email or SMS) instead of dropping the user.