Everything smashsend.com publishes
S

smashsend.com

SMASHSEND Contact Properties API Reference

/docs/api/contact-properties

docs
Words
727
Reading time
3 min
Last crawled
2026-09-27
Language
EN

Opening

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

SMASHSEND Contact Properties API Reference1 / 7

Overview

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.

SMASHSEND Contact Properties API Reference2 / 7

Contact Properties Endpoints

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

SMASHSEND Contact Properties API Reference3 / 7

Property Types Reference

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

SMASHSEND Contact Properties API Reference4 / 7

Using Properties with Contacts API

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

SMASHSEND Contact Properties API Reference5 / 7

Common Integration Examples

CRM Integration Properties E-commerce Integration Properties Form Integration Properties

SMASHSEND Contact Properties API Reference6 / 7

Error Handling

400 - Validation Error 409 - Property Already Exists

SMASHSEND Contact Properties API Reference7 / 7