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SMASHSEND Contacts API Reference

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Home / Docs / API Reference / Contacts The Contacts API allows you to manage contacts in your SMASHSEND account. This API is commonly used by Zapier developers and other integration platforms to sync contact data, create

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Authentication & Base URL

Base URL: All API requests must include your API key in the Authorization header. You can manage your API keys in your SMASHSEND dashboard under Settings → API. Rate Limits: API requests are limited to ensure service rel

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Contacts Endpoints

GET/v1/contacts Lists contacts for the authenticated workspace with cursor-based pagination. Perfect for Zapier “New Contact” triggers and bulk contact synchronization. Request Response GET/v1/contacts/{contactId} Retrie

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Error Handling

The API uses standard HTTP status codes. Common error responses: 400 - Bad Request 404 - Not Found 409 - Conflict

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Custom Properties

Custom properties allow you to store additional data with contacts. They're commonly used to sync data from CRMs, e-commerce platforms, and other business tools via Zapier. Before using custom properties in API calls, yo

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Zapier Integration Tips

1. Use “Search then Create” Pattern Always search for existing contacts by email before creating new ones to avoid duplicates. 2. Leverage Custom Properties Use custom properties to sync additional data from your source

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Working with Timezones

SMASHSEND supports timezone-aware email delivery to maximize engagement by sending emails at optimal times in each contact's local timezone. The field accepts IANA timezone identifiers and enables smart delivery features

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Working with Country Codes

The field stores the contact's country using ISO 3166-1 alpha-2 country codes. Country Code Field Type: String (optional) Format: Two-letter ISO 3166-1 alpha-2 code (e.g., , , ) Validation: Must be a valid ISO country co

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Working with Language Codes

The field stores the contact's preferred language using ISO 639-1 language codes. Language Field Type: String (optional) Format: ISO 639-1 two-letter code (e.g., , , ) or locale format (e.g., , ) Validation: Must be a va

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Complete Integration Example

Here's a complete example showing how to detect and send all geographic/locale data from a web form using explicit detection (recommended): Accuracy Recommendations 1. Always Use Explicit Timezone Detection: Use in brows

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