# Phone Number Collection

{% hint style="warning" %}
**Is the estimated send count not updating even after changing the campaign's target audience?**

Check whether users' phone numbers are being collected correctly.
{% endhint %}

{% hint style="info" %}
Phone number collection is required to send Kakao Messages and Text Messages.\
Below are several methods for collecting phone numbers.
{% endhint %}

## Collecting Phone Numbers via SDK

You can collect phone numbers of users who have signed up for your service using the Hackle Client SDK.

## Collecting Phone Numbers via HTTP API

In addition to the Client SDK, you can also collect phone numbers using the HTTP API.

e.g.) When phone numbers need to be collected or updated server-side, such as in an admin interface.

## Collecting Phone Numbers via Import

You can import phone numbers for all users who signed up before your SDK/API integration in a single batch.

For details, refer to the CSV example below and send the file you want to import to the [Hackle team](mailto:support@hackle.io).

### CSV Example

User ID and phone number are required fields. Other information can be requested as needed.

For details, please contact the Hackle team.

| User ID        | Phone Number | Marketing Subscription Consent (Optional) |
| -------------- | ------------ | ----------------------------------------- |
| hackle\_richie | 01012345678  | 1                                         |
| hackle\_limo   | 01098765432  | 0                                         |


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