You can create a Contact List by uploading CUser ID also known as a Customer ID (Retailer ID).

Upload manually into the platform

You must upload one file per audience.
Accepted file formats: .csv, .txt, or .tsv.
File names can include any characters except: *, ?, `, <, >, |, :, ", /, and \.
Non-UTF-8 characters are not permitted.

File Size:
- Minimum: 500 valid rows.
- Maximum: 1 million rows (30MB). This limit ensures optimal upload performance.

A minimum match rate of 0.1% is required, calculated as (number of matches / total lines).

The file must contain data; empty files are not allowed.

Import via SFTP

The retailer is expected to upload one file per audience.
The file should contain one cUserID per line.
The file extension is not mandatory but recommended (.csv or .txt). Compressed files are not supported (.tar/.zip).
Any file name should be accepted (alphanumeric only + hyphen + underscore) and capital letters should be lowercase.
Each file dropped on our SFTP servers will be a dedicated segment. If the audience needs to be updated, a file with the same name should be dropped on our servers.
A Customer list can include up to 600 millions of cUserID  (min. 1000 IDs matched).

Import via API

Retailers need to go through the API authentication mechanism and use Retail Media Audience Segment API endpoints.
The only limitation via API is the number of IDs that can be pushed in one request (50,000 identifiers max per single request)

To learn in detail all the technical aspects and guidelines to follow for importing your Contact Lists via API, check out our guide Audience Segment Endpoints.

What's New January 2025