Contact properties

Add a property

Open Audience → Properties and click Add property:

• Key: lowercase letters, numbers and underscores, starting with a letter, up to 50 characters, for example company_name. The contact page labels it Company Name.
• Type: String or Number.
• Fallback value: optional. Used in emails when a contact has no value for this key.

Then fill the property on each contact's page, through a CSV import, or through the API.

The list also shows the four built-in fields with a Default badge: email, first_name, last_name and unsubscribed. These keys are reserved and cannot be used for custom properties.

Change or delete a property

A property's key and type cannot change after it is created. Through the API, update a property to change only its fallback_value. Delete removes the property and its value from every contact.

Use the API

{"key":"plan","type":"string","fallback_value":"starter"}

API keys keep their spelling and allow letters, numbers and underscores (1–50 characters). On a contact, set a property by key; null or an empty string clears it so the fallback applies.

Limits

• A team can have up to 100 properties.
• Only string and number values; there are no boolean properties.
• Values are up to 1000 characters.