How to Sync Audiences to Custom Audience

This guide walks you through the process of syncing a saved audience to your Custom Audience destination.

To set up the Custom Audience destination in RudderStack, see Custom Audience Setup Guide.

Prerequisites

On your audience platform

• A target audience list created on your platform — note its Audience ID

In RudderStack

• Set up an Audience
• Set up a Custom Audience destination

Add sync

1. Open the audience’s Syncs tab and click Add sync.
2. Select Custom Audience, then select the required Custom Audience destination.
3. Configure the following settings to specify the target audience and map your warehouse data:

Specify target audience

Create the audience on your platform before entering these values. RudderStack does not create audiences at the destination for this integration.

Sync mode

RudderStack supports only Mirror mode for this integration.

On the first run, the full membership is sent to the platform. Later runs send only inserts, updates, and deletes.

Map identifiers

Map warehouse columns to each template field defined in the Custom Audience destination.

You can map two types of fields:

• Warehouse fields: Dropdown of warehouse columns
• Static fields: Specify literal values for fields configured as Static in the destination settings

Required destination fields appear with an asterisk (*) during mapping.

Advanced settings

Sync settings

Two options are available to schedule your audience syncs:

• Run syncs automatically based on a specified frequency (every 5 minutes, 10 minutes, 15 minutes, 30 minutes, 1 hour, 3 hours, 6 hours, 12 hours, or 24 hours) and a specific time (in UTC).
• Run syncs manually — trigger a sync from the sync details page. You will need to run the sync each time.

Sync observability settings

Storing sync logs and snapshot tables may incur additional warehouse costs.

Enable sync

Once the setup is complete, enable the sync.

Data hashing

The Automatically hash PII data setting lets you hash your user data before sending it to your API.

• Configure the setting to Yes if your incoming data is not pre-hashed
• Configure this setting to No if your data is already hashed

Incorrect configuration of the Automatically hash PII data setting will result in failures.

• If the Automatically hash PII data setting is configured to Yes and your data is pre-hashed, the event will fail.
• If the Automatically hash PII data setting is configured to No and your data is not pre-hashed, the event will fail.

Such events are rejected with a clear error message, for example:

Hashing is disabled but the value for field EMAIL appears to be unhashed. Either enable hashing or send pre-hashed data.

You will also see errors in the Events tab for cases that were previously marked as successful but resulted in no matches, helping you identify and fix data quality or configuration issues.

Troubleshooting