Import Email Addresses

How to import email addresses from your server to use OneSignal Email Messaging

This guide explains how to upload a CSV list of email addresses through the dashboard or manually add emails if needed. Other options include:


Duplicate Email Records

OneSignal will automatically remove duplicate email subscriptions. If the email subscription is marked as unsubscribed, it will continue to be marked unsubscribed unless updated.

Import Emails through Dashboard

Within Audience > Subscriptions you can import a CSV list of email addresses or add email addresses manually.

CSV Upload


CSV Email Upload Requirements

  • Must have email column with lower-case spelling
  • Limited to UTF-8 Encoding
  • Columns must be unique
  • No quotes
  • Commas only, no semi-colons

The CSV must have an email column containing the addresses. It is recommended to include the external_id column to identify the user that owns the email address. See Aliases & External ID for details.

If you want to include email addresses that have opted-out of receiving messages, set the subscribed column to yes or no. Without this column, it defaults to all addresses opted-in (yes).

The CSV can include Data Tags for segmentation and Message Personalization as well as update the subscription status. Set the tag key for the column and the value under it.

Example CSV:


Navigate to Audience > Subscriptions > Update/Import Users.

Under "Import email(s)" select Upload CSV. There is also a CSV Template you can download to check your format.

Which columns would you like to import as tags?

Checked columns will be imported as tags. Uncheck the columns you do not want set as tags.

Advanced Settings

If you want to create a segment to send messages to this list, toggle on the Automatically create a segment for this import to set a new tag and create a segment for these users.

Delete identifier and tag values if columns are empty

Check this option if you want to delete the tag on the user if the key is present on the user and no value set in the CSV.

Review and click Confirm and Update when ready to import. You will get an email to the current address when the upload is finished.

Manually Add Emails

Navigate to Audience > Subscriptions > Arrow next to Update/Import Users > Manually Add Emails to open a new modal where you can add an individual user's email and tag data.



Once you've imported your emails, go back to Email Quickstart to determine if you have any steps left.