Please consider the following when choosing the unique identifier:

• If you have a custom alphanumeric ID field in your file instead of email addresses, select that field from the drop-down.
• If you have email addresses in your file and you would like to use the sales data API, select a Predict user ID field.
• If you would like to use the SFTP server and you have email addresses in your files, select the email field as the unique identifier.

Changing the unique identifier after the Smart Insight setup severely impacts the Emarsys Loyalty Add-On. In such a case, you need to reimplement the add-on.

You can choose a unique identifier only from the Contact Fields that are offered to you on the UI. You can check the identifier fields generated and used internally by Emarsys on the Data Export page, for example, user ID / contact ID. Do not rely on these in any way, using our internal variables outside Emarsys as identifiers is considered a risky implementation practice.

Changing the contact identification method in Web Extend may break your Smart Insight integration if it receives sales data via the Web Extend data collection scripts.

To avoid breaking your Smart Insight integration, after changing the contact identification method in Web Extend you need to modify your Smart Insight settings as follows:

1. Change the unique ID on the Contact Fields tab according to your new Web Extend settings.
2. Prepare a sample CSV file where you need to remap the purchase data fields so that they include the customer ID.
3. Stop uploading the delta files to Predict, then empty the Smart Insight database.
4. Perform a full historical data reload with the sales data containing the new identifier into Smart Insight via Predict. Please contact Emarsys Support to perform this action.
5. Optionally, if you use your own product catalog instead of the Predict product catalog, upload a historical catalog to the Smart Insight SFTP as well.

• If you would like to use Web Extend, make sure you have already implemented the Web Scripts data collection scripts in your store, otherwise you will not be able to use the Web Extend web behavior fields for filtering.
• If you use email as the Contact identifier in your sales data file and you send your sales data via the Sales data API, then Emarsys will hash the email addresses and this field will change to predictUserId. In this case, you need to change the Unique identifier to predictUserId on the Smart Insight Settings > Contact Fields tab. This is how your settings should look like:

• If you upload the sales data into Smart Insight via Sales data API or JS API and use, for example, email as the Unique identifier and you use the same Unique identifier during upload (regardless of which method you use), then the email addresses will be hashed and the Unique identifier will change to predictUserId. As a result, the number of unidentified contacts and sales data that is not attributed to contacts (i. e. the result of duplication) will increase. To prevent or fix this issue, set the Unique identifier to predictUserId on the Smart Insight Settings > Contact Fields tab and do the same during the upload.

Furthermore, if you have already uploaded sales data via Predict or JS API and used email as the Unique identifier, then you can fix this issue by changing the Unique identifier to predictUserId on the Smart Insight Settings > Contact Fields tab and by doing the same during the next upload to sync all data.

• If you change the Unique identifier in the contact fields and the Contact identifier in the sales data file, then it will not create duplicate contacts in the Smart Insight database. In this case, you don’t need to reload your data because the contacts will be identified retrospectively during the next data load.