Create, delete, and edit Custom data fields

Learn how to create and delete custom contact data fields. 


As well as the default contact data fields already in place in your address books, for example, FIRSTNAME, FULLNAME, LASTNAME, you can create new custom contact data fields to capture and hold additional information about your contacts.

The more useful data you can collect on your contacts, the more you can usefully segment, target and personalise your campaigns and in turn generate better response rates.

When you create a contact data field, it's added to all of the address books in your account. This way, all of your address books maintain the same structure.

Limits of contact data fields

The total number of data fields you can create and their individual limitations:

Data field type Maximum allowed Limit for each data field
Text 295 1,000 characters
Numeric 100

27 digits

  • Up to 9 digits can be after a decimal marker
  • Up to 18 digits can be before a decimal marker
Date 99 -
Yes/No 100 -

There are an additional six default data fields that cannot be renamed used to store first name, last name, full name, gender, last subscribed and postcode.

Create a contact data field

To create a new contact data field.

  1. Go to Email > Contacts > Contact data fields.
  2. Select the Custom data fields tab and then select NEW DATA FIELD. 
  3. For Name, enter a unique name for your contact data field.
    • You can't use spaces between words when creating a name for a new field.
    • There are some names you can't use for data fields. For a list of restricted data fields, check out Restricted data field values.
  4. For Data type, expand the Data type drop-down menu and select a data type.
    There are four data-types: Text, Numeric, Date (use ISO 8601 format), and Yes/No.
  5. For Default value, if you want, enter a default value for the contact data field in case it's not filled in after uploading your data.
    To learn more, check out the article Set a default value for a contact data field.
  6. For Access, select either:
    • This data label is public
      To let your contacts view and amend the data you hold on them for this contact data field.
    • This data label is private
      To only let users of your account view and amend data held in this contact data field.
  7. For Folder, expand the folder drop-down menu, and choose which folder you want to save the contact data field in.
  8. Select Save.

You can also create contact data fields in the Data fields tab when viewing and editing a contact.

If you're storing telephone numbers

We advise using the text data type for contact data fields storing phone numbers or prices, instead of the numeric data type.

The numeric data type removes 0 values, for example, phone numbers beginning 07xxxxxxxxx will have the first 0 removed and 9.50 will become 9.5. If you use the text data type, the data maintains 0 values as part of the string.

Delete a contact data field

You can delete any of the contact data fields you create. To delete a contact data field:

  1. Go to Email > Contacts > Contact data fields.
  2. Select the Custom data fields tab.
  3. Find the data field you want to delete and select the X to delete.
    You can’t delete the default contact data fields, for example, FIRSTNAME, FULLNAME.

Are you sure you want to delete a data field?

Deleting a contact data field also means deleting any of the data you already have stored under it. In which case, you need to be certain that you don't mind losing the data before you delete a contact data field.

If you don’t want to lose any data, export your contacts from the application, and then import the data back in after deleting the contact data field you want to delete.

Edit contact data field properties

You can change the non-critical properties of contact data fields but you can't edit any critical properties.

Critical, non-editable properties Non-critical, editable properties


Default value

Data type




To change the non-critical properties of your contact data fields:

  1. Go to Email > Contacts > Contact data fields.
  2. Select the Custom data fields tab.
  3. Find the data field you want to change the properties of
  4. Select the Properties icon next to the field.
  5. Edit your properties for Default value, Access, or Folder.
    To learn more about these, check out the section Create a contact data field.
  6. Select Save.

Why you can't change critical properties

There's a good reason why we don't allow you to edit critical properties. If you could, any existing information you hold; for example, date and time values, stored correctly under a date data type; could then be switched to a different data type and the data type recognition would fail.

If you could change the name of an existing contact data field, then any existing data mapping would break. This is why they're strictly non-editable. 

If you’re looking to change a name or data type, the best way to do this is to delete and then recreate the contact data field, whilst exporting and then re-importing any data that you wish to keep, as outlined above.

Change the contact data fields display view

To change your view on the contact data fields page.

  1. Go to Email > Contacts > Contact data fields.
  2. Select the Customdata fields tab.
  3. Select Display.
  4. For Sort by, expand the drop-down menu, and select to sort contact data fields into ascending or descending order based on an attribute, for example, Name, Data type, Access, Created, or Modified.
  5. For Folders, select Yes to show your data fields in their folders.
    Select No if you don't want to see folders.
  6. For Visible columns, select or clear the check boxes to view or hide specific columns. 
  7. Select Submit.

Restricted data field values

There are various words you can’t use to create data fields.

The restricted data fields:

  • account
  • campaign
  • campaignid
  • contact
  • contact_api_id
  • contactid
  • email
  • hcontactid
  • hemail
  • hemail256
  • id
  • messagecontent
  • notes
  • unsubscribed
  • uniquecontactid
  • mobilenumberid

See also

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