Push Notification Doze Gate: Priority, Collapse-Key & TTL

Traffic

Send rate 4.0 msg/s

High-priority share 20%

Doze closed window 4.0 s

Message TTL 6.0 s

Gate State

device idle CLOSED

Live Readouts

Queued (waiting)

Delivered

TTL-expired

Collapsed (deduped)

Avg latency

0 ms

Total sent

How it works

Real push services (FCM, APNs) attach three fields to every message that decide what happens when the target device is asleep:

priority: "high" | "normal"
collapse_key: string | none
time_to_live (TTL): seconds

Priority. A high-priority message wakes the device's radio immediately, Doze or not — used for calls, chat messages, alarms. A normal-priority message is deferred until the OS's next scheduled network-access window.
Doze / App Standby. When a device is idle and stationary, Android batches network access into periodic maintenance windows to save battery. Outside a window the gate is closed: normal pushes pile up at the gate, high-priority pushes still pass straight through.
Collapse-key. If a new message arrives with the same collapse_key as one still waiting undelivered, the server (and the device) only need to keep the newest — older duplicates for that key are discarded on arrival ("collapsed"), exactly like a badge-count update superseding a stale one.
TTL. Every queued message carries a deadline. If the Doze window doesn't open before its TTL elapses, the message is dropped and never delivered — silently, with no retry.

This sim keeps its own clock: the send rate and high-priority share sliders control the message stream, the Doze closed window slider controls how long the gate stays shut, and the TTL slider decides how many queued messages expire before the gate reopens. Toggle Doze off to see a plugged-in / actively-used device, where every message reaches the phone immediately.

High priority Normal priority Queued at gate

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