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How it works

Before you can take advantage of our SDK, you need to install the module(s) you want to use, initialize the SDK, and understand the order of operations.

Our SDKs provide a ready-made integration to identify people who use mobile devices and send them notifications. Before you start using the SDK, you should understand a bit about how the SDK works with Customer.io.

Before a person logs into your app, any activity they perform is associated with an anonymous person in Customer.io. In this state, you can track their activity, but you can’t send them messages through Customer.io.

When someone logs into your app, you’ll send an identify call to Customer.io. This makes the person eligible to receive messages and reconciles their anonymous activity to their identified profile in Customer.io.

You send messages to a person through the Customer.io campaign builder, broadcasts, etc. These messages are not stored on the device side. If you want to send an event-triggered campaign to a mobile device, the mobile device user must be identified and have a connection such that it can send an event back to Customer.io and receive a message payload.

Your app is a data source and Customer.io is a destination

Our SDK is a data sourceA source is a website or server that you want to capture data from—it’s a source of data! in Customer.io Data PipelinesCustomer.io’s customer data platform, helping you capture data from your sources, transform it, and send it to destinations where you can act on it. Data Pipelines is also the preferred integration path for your Customer.io workspace, as it supports all of our Journeys features and other destinations that rely on your data.. It routes data from your app to both Customer.io and any other destinations where you might use your mobile data. This makes it easy to use your app as a part of your larger data stack without using extra packages or code.

When you set up your app, you’ll integrate our SDK. But you’ll also determine where you want to route your data to—your Customer.io workspace and destinations outside of Customer.io.

Minimum requirements

To support the Customer.io SDK, you must:

• Use Android Gradle plugin version 7.4 or later.

• Have an Android device or emulator with Google Play Services enabled and a minimum OS version between Android 5.0 (API level 21) and Android 13.0 (API level 33).

Kotlin Serialization

We offer a Kotlin serialization library that can help make it easier to set keys and values for the traits object. If you used an older version of the SDK, you can still use the classic methods for setting parameters in SDK calls. Otherwise, you can use the Kotlin serialization library to set keys and values when you call the SDK; we provide samples for both methods in this guide.

Here’s an example of the method signature for the serialized identify call:

fun identify(userId: String, traits: JsonObject)

// If <T> is annotated with @Serializable you will not need to provide a serializationStrategy
fun <T> identify(userId: String, traits: T, serializationStrategy: KSerializer<T>)

The Processing Queue

The SDK automatically adds all calls to a queue system, and waits to perform these calls until certain criteria is met. This queue makes things easier, both for you and your users: it handles errors and retries for you (even when users lose connectivity), and it can save users’ battery life by batching requests.

The queue holds requests until any one of the following criteria is met:

• There are 20 or more tasks in the queue.
• 30 seconds have passed since the SDK performed its last task.
• The app is closed and re-opened.

For example, when you identify a new person in your app using the SDK, you won’t see the created/updated person immediately. You’ll have to wait for the SDK to meet any of the criteria above before the SDK sends a request to the Customer.io API. Then, if the request is successful, you’ll see your created/updated person in your workspace.