What it does:
With CSV Upload you can:
Add customers who are not in your CRM, DMS or website data.
Add your own fields (custom attributes) to customers you already have.
Before you start
Each row needs at least one identifier: User ID, email or phone.
The rest of the columns can be anything you want!
How to upload
First, open Customers → Imports and click New Import.
Select your CSV file.
Map your columns:
Map email, phone, User ID or name. These are used only to match customers.
Map each other column to a custom attribute you already have, or create a new one. To create one, give it a name and a data type.
Submit the import. It shows at the top of the Imports list with the status Processing.
After you upload
The status changes to Complete or Failed. If it fails, click Retry.
You can download the original file from the Imports list.
New customers and custom attributes show in Audience Builder within 24 hours. You can filter on custom attributes there.
Each import also makes its own audience that you can use in Workflows.
Good to know
CSV upload does not change name, email, phone or other default fields. It only adds or updates custom attributes.
If a row matches a customer you already have, that customer gets the new values. If there is no match, a new customer is made.
You cannot undo an import or edit the mappings after you submit. To fix a mistake, upload a corrected file.
Custom attributes stay in the organization where you upload them. A group organization does not get them from its stores.
A custom attribute name must be unique and cannot be the same as a default field name.

