# One push. A million phones.

> Why looping over device tokens is the answer that fails the interview.

- **Format:** short video, 10 steps, ~32 seconds
- **Topic:** Azure Notification Hubs — why pushing one message to a million phones is a platform problem, not a loop.
- **Author:** Suthahar Jegatheesan (MSDEVBUILD)
- **Category:** Azure · Azure
- **Tags:** azure, notificationhubs, pushnotifications, azurenotificationhubs, systemdesign, mobiledevelopment, microsoftazure, azurecloud, cloudarchitecture, dotnetmaui, backenddeveloper, az305, msdevbuild
- **Canonical URL:** https://blog.msdevbuild.com/shorts/azure-notification-hubs-broadcast/

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## What you'll learn

- Why a loop over a million device tokens finishes too late
- How one send becomes APNs, FCM and WNS payloads
- How tag targeting replaces holding device tokens yourself

## Understand it one step at a time

### 1. Send this to a million phones

One line of copy, one send button, and 1,000,000 devices that need to hear about it.

### 2. Three platforms, three of everything

APNs wants a .p8 key, FCM wants a service account, WNS wants a package SID. Different payloads too.

### 3. The loop finishes tomorrow

A million sequential HTTP calls at 44 a second. The sale it was announcing ended hours ago.

### 4. Fix: Azure Notification Hubs

One send to the hub. It holds the credentials, the registrations and the per-platform payloads.

### 5. The hub speaks every platform

One call becomes an aps payload, an FCM notification and a WNS toast. You wrote none of them.

### 6. Target by tag, not by device

Devices register with tags. You send to “city:bengaluru AND tier:prime” and never touch a token.

### 7. Dead tokens clean themselves

Uninstalled apps get rejected by APNs and FCM, and the hub removes those registrations for you.

### 8. A push is not a message queue

No ordering, no retention, no receipt. If it must arrive, it belongs in your app, not in a banner.

### 9. Your loop vs the hub

The same push, and the difference is how much delivery machinery you are on the hook for.

### 10. Send once. Reach a million.

Your code should describe the audience and the copy. Everything below that is the hub’s job.

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## The takeaway

**Describe the audience, not the devices**

The moment your push code knows what a device token is, you own a delivery platform.