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Overview

This API allows you to add a new Subscription to an existing User via an alias identifier. A Subscription reflects a user’s intent to receive messages through a specific communication channel, such as email, SMS, or push notifications. See Subscriptions for additional context. If you’re looking to create a new user and add Subscriptions simultaneously, use the Create User API instead.

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How to use this API

To attach a Subscription, the user must already exist and be referenced using an alias. The alias_label and alias_id path parameters define how the user is identified:
  • Common alias: external_id
  • Other options: onesignal_id, or custom aliases
For details, refer to Users and Aliases.

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Required Fields

Each Subscription must include at least:
  • type: the channel (e.g., Email, SMS, iOSPush)
  • token: the unique identifier for the channel (e.g., email address, phone number, push token)
If the specified type and token already exist in the app, the Subscription will be transferred to the user identified in the path parameters.