> This page is part of the [Customer.io documentation](https://docs.customer.io). For the complete index, see [llms.txt](https://docs.customer.io/llms.txt).
> Last updated: October 28, 2026
> To take actions in Customer.io from an agent, use the [Customer.io CLI](https://docs.customer.io/ai/cli/get-started.md) or the [MCP server](https://docs.customer.io/ai/mcp/get-started.md).

# Push notifications on mobile and web

Customer.io sends push notifications to iOS and Android apps and to web browsers. Learn how mobile push and web push differ, what they have in common, and where to start.

Push notifications reach people on their phones, tablets, and web browsers, even when they aren’t using your app or visiting your website.

We support mobile push notifications (iOS and Android) and web push notifications. The two kinds of push have different setup steps, but they work similarly when you send messages. This page compares them and explains what they have in common.

## Mobile and web push at a glance

You don’t have to choose between mobile push and web push. You can set both up and send messages to both platforms from the same automation.

[Mobile push](https://docs.customer.io/messaging/channels/push/getting-started/)

[Web push](https://docs.customer.io/messaging/channels/web-push/overview/)

**Who it reaches**

People who installed your iOS or Android app

People who visit your website in Chrome, Edge, Firefox, or Safari

**What your developers set up**

Our [mobile SDK](https://docs.customer.io/integrations/sdk/) in your app

Our web push plugin for the [JavaScript integration](https://docs.customer.io/integrations/data-in/connections/javascript/js-source/), and a service worker file on your website

**Credentials**

Your Apple (APNs) or Firebase (FCM) credentials, which you add in [**Workspace Settings** > **Push**](https://fly.customer.io/workspaces/last/settings/actions/apps)

A key pair that Customer.io generates for you in [**Workspace Settings** > **Push** > **Web**](https://fly.customer.io/workspaces/last/settings/actions/push/web). You don’t need an account with a push provider.

**What you can send**

Standard push, rich push, and custom payloads

Rich push with an icon, an image, and up to two action buttons

**How people opt in**

A person allows notifications for your app

A signed-in visitor clicks a button on your site and allows notifications in their browser

## Devices

Customer.io registers each app install or browser where a person allows notifications as a *device* on their profile. Every device has an ID, a platform (`ios`, `android`, or `web`), and the time the person last used it. You can see a person’s devices on the **Devices** tab of their profile.

For an app, the device ID is the token that Apple or Firebase gives your app. For a browser, the device ID is the subscription endpoint, a URL that the browser’s push service gives your website. See [web devices](https://docs.customer.io/messaging/channels/push/device-tokens/#web-devices).

## Which devices get a message

When you set up a message, you choose which platform it sends to: mobile (iOS and Android) or web. Transactional push can also send to both. Customer.io only sends your notification to devices on the platform you choose:

*   In an **automation**, mobile push and web push are separate actions:

    *   A **Push Notification** action sends to iOS and Android devices.
    *   A **Web Push** action sends only to browsers.

    People who turn on notifications in a browser don’t start getting your app’s messages there. To reach both a person’s phone and their browser, add both a **Push Notification** action and a **Web Push** action.

*   A **one-time send** lets you pick the platform: mobile or web.

*   **Transactional push** sends to iOS and Android by default. You can change the message’s platform to **Web** or **iOS, Android & Web** to include web browsers. See [send transactional web push](https://docs.customer.io/messaging/channels/web-push/transactional/).

 ![An automation workflow with a Web Push action followed by a Push Notification action, next to the Add panel that lists Push Notification and Web Push as separate actions](https://docs.customer.io/images/push-and-web-push-actions.png)

### Last used device

When you set a message to go to the last used device, Customer.io picks the most recently used device on the message’s platform. For example, if you send a mobile push notification to a person who has three mobile devices and no registered web devices, they’ll get their notification on the device that was most recently updated with Customer.io.

If you send a web push notification using the last-used device option, that same user wouldn’t get the notification at all because they don’t have a registered web device (browser).

## Subscription preferences

Unsubscribe and [subscription preferences](https://docs.customer.io/messaging/channels/subscriptions/overview/) apply to push-eligible devices. In your subscription center, the **Push notifications** channel covers both mobile devices *and* web browsers by default.

If you want people to be able to turn off browser notifications and keep app notifications, or the other way around, add a [**Web browsers** channel](https://docs.customer.io/messaging/channels/subscriptions/overview/#web-browsers-channel) to your subscription center.

## Metrics and delivery statuses

Mobile and web push notifications report the same delivery statuses and metrics. On mobile devices, our SDK reports them from your app. On the web, the Customer.io service worker on your website reports them from the browser. When an automation has both **Push Notification** and **Web Push** actions, its **Overview** can show push metrics for iOS, Android, and Web separately. Filter the overview to the **Push** channel to see them. See [push metrics and message statuses](https://docs.customer.io/messaging/channels/push/notifications-tracking/#web-push-metrics).

## Segments

You can build segments on a person’s devices, and **Web** is one of the platforms you can filter on. See [device segments](https://docs.customer.io/messaging/segmentation/device-segments/).

Check your **Have a Mobile Device** segment before you send web push. In workspaces created before web push, this default segment includes everyone with any device, so it also includes people who only have browsers. See [check your Have a Mobile Device segment](https://docs.customer.io/messaging/segmentation/device-segments/#have-a-mobile-device).