Push notifications iOS interview question

Push sits between iOS fundamentals and system design, so it is a common question with rich senior follow-ups about reliability and delivery.

The end-to-end flow

The app registers for remote notifications and receives a device token, which it sends to your server. To deliver a notification, your server sends a payload to Apple Push Notification service, which routes it to the device. The system displays it, or wakes the app for a background or silent push, subject to the payload's content and priority.

The senior follow-ups

Be ready for token rotation and storing tokens server-side, best-effort delivery so pushes are not guaranteed and should not carry critical state, silent pushes for background refresh and their throttling, notification service extensions for modifying payloads, and handling taps to deep link into the right screen. Framing push as unreliable transport for hints, not a data channel, is the senior insight.

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Share Your Screen works topics like this through in full: 75 solved Swift problems with tests, 9 real case studies, and 7 annotated mock interviews, so you rehearse the live round instead of just reading about it.

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Frequently asked

Are push notifications guaranteed to be delivered?

No. APNs is best-effort, so notifications can be dropped or coalesced. Do not rely on them for critical data; treat them as hints and fetch the source of truth.

What is a silent push?

A content-available background notification that wakes the app to fetch data without showing UI. The system throttles them, so delivery and timing are not guaranteed.