SMASHSEND Contact Properties API Reference

Home / Docs / API Reference / Contact Properties The Contact Properties API allows you to create and manage custom fields for contacts. This is essential for Zapier integrations and other automation platforms that need t

Contact properties are custom fields that extend the default contact schema. Common use cases include storing job titles, company information, lead sources, subscription preferences, and any other business-specific data.

GET/v1/contact-properties Lists all contact properties for the authenticated workspace. Perfect for Zapier integrations to dynamically discover available custom fields. Request Response GET/v1/contact-properties/{propert

STRING Short text values, ideal for names, categories, statuses. Maximum 255 characters. TEXT Long text values for descriptions, notes, comments. No character limit. EMAIL Email addresses with automatic validation. URL W

Once you create contact properties, you can use them in the Contacts API by referencing their apiSlug in the customProperties object:

CRM Integration Properties E-commerce Integration Properties Form Integration Properties

400 - Validation Error 409 - Property Already Exists