You can create up to 10 custom IDs per account.
Learn more in Understand custom identifiers.
Create a custom ID
Select the Account menu icon and go to Settings > Contacts > Custom identifiers.
Select New custom identifier.
Enter a name for the custom ID.
Names can be up to 50 characters. They can contain only letters, numbers, hyphens or dashes, and underscores. A name can't match an existing custom contact data field.
Select Create.
The custom ID starts empty for every contact. Existing contacts don't get a value automatically - import a file or edit contacts individually to add one.
Learn more in Use custom identifiers.
Delete a custom ID
When you delete a custom ID, you also delete all its values for every contact. This is permanent. You can't reverse it or recover the values from the recycle bin.
Deleting a custom ID doesn't delete the contacts themselves or their other data.
Select the Account menu icon and go to Settings > Contacts > Custom identifiers.
Find the custom ID you want to delete, then select the Delete icon (X) at the end of the row.
Read the information in the popup, then enter Delete in the text field.
Select Delete.
The custom ID and all its values are deleted straight away.
Use custom identifiers
Display, search, import, edit, and personalise content with custom IDs across Marketing.
After you create a custom ID, you can use it throughout Marketing to view and manage your contact data.
Learn more about the rules custom IDs follow in Understand custom identifiers.
Show custom IDs in tables and grid views
You can add custom IDs as columns in the contact tables and grid views in these areas:
the Contacts area
lists
segments
marketing preferences
the Suppressions area
In the grid view, select Display in the top right.
In the Table display settings side panel, search for the custom ID you want to display.
Select the checkbox for the custom ID, then select Apply.
The custom ID appears as a column in the grid view.
Search by custom ID
You can search by custom ID in the Contacts area, and in lists, segments, and marketing preferences.
In the search bar at the top of the screen, expand the drop-down menu and choose the custom ID you want to search by.
The default is Email.
Enter your search value.
Select the search icon or press Enter.
Import custom IDs from a file
You can include custom IDs as columns in a CSV or XLSX file import. Follow the usual import process. If a column name matches the name of a custom ID you've created, Marketing maps it automatically.
If a custom ID column isn't mapped automatically, expand the Map to contact data field drop-down menu for that row on the Data mapping screen and choose the custom ID.
Each custom ID value must be unique to one contact, and you can't overwrite an existing custom ID value with a file import.
Learn more in Upload multiple contacts and Use the scheduled contact importer.
View and edit custom IDs on the Single customer view
View a contact's custom IDs
In the Contacts area, a list, or a segment, use the search bar to find the contact.
Select the contact's email address or mobile number to open their Single customer view.
The contact's custom IDs and their values appear in the top left of the Overview tab.
Edit a contact's custom IDs
On the Overview tab, select the Edit icon (pencil) next to the contact's name, or select the Data fields tab.
In the Personal details folder, under Identifiers, enter or update the value for the custom ID.
Select Save.
Personalise content with custom IDs
You can use custom IDs to personalise email, SMS and MMS, and WhatsApp campaigns, and program webhooks.
Email campaigns, surveys, pages, and forms
You can add custom ID values to email campaigns, pages, and forms in the same way as data fields. This works in both the HTML and plain text versions of email campaigns.
You can also insert custom IDs into the URL of an External dynamic content block.
Learn more in personalise content with data fields.
SMS and MMS campaigns
You can use custom IDs as personalisation markers in SMS and MMS campaigns.
Use custom IDs with the API
You can use custom IDs with the Contacts and Insight data API services.
Learn more in Unified contacts on the Developer Hub.