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Overview

The OpenPhone API enables developers to integrate OpenPhone’s communication capabilities directly into their applications and workflows. Send messages, manage contacts, and automate communication processes programmatically.
API access requires an active OpenPhone subscription and Owner or Admin permissions for your workspace.

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Getting started with the API

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Prerequisites

Requirements for API access:
  • Active OpenPhone subscription (any plan)
  • Owner or Admin role in your workspace
  • Completed US carrier registration for messaging to US numbers
  • Prepaid credits for API messaging

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API documentation

Access comprehensive API documentation and resources: Available in our API documentation:
  • Step-by-step setup and authentication
  • Complete endpoint reference
  • Code examples and SDKs
  • Rate limits and best practices
  • Pricing and billing information

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API capabilities

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Core functionality

Available API endpoints:
  • Send messages: Programmatically send SMS/MMS
  • Manage contacts: Create, update, and organize contacts
  • Retrieve conversations: Access message history and threads
  • Webhook integration: Receive real-time event notifications

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Messaging features

Supported message types:
  • SMS text messages to US, Canadian, and international numbers
  • MMS messages with media attachments
  • Group messaging capabilities
  • Message status tracking and delivery confirmation

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Pricing and billing

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API message costs

Prepaid credit system:
  • US and Canadian messages: $0.01 per message segment
  • International messages: $0.01 per segment + international rates
  • Prepaid credits required: Purchase through billing settings
  • No monthly API fees: Pay only for messages sent
API messaging requires prepaid credits. Messages will fail if insufficient credits are available.

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Message segments

How message segments work:
  • Standard SMS: 160 characters = 1 segment
  • Unicode/emoji SMS: 70 characters = 1 segment
  • Longer messages automatically split into multiple segments
  • MMS messages count as single segment regardless of content size

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Authentication and security

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API keys

Secure authentication:
  • Generate API keys through workspace settings
  • Keys provide secure access to your workspace data
  • Regenerate keys if compromised
  • Use environment variables to store keys securely

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Rate limits

API usage limits:
  • Designed to prevent abuse and ensure reliability
  • Limits vary by endpoint and subscription level
  • Monitor usage through API responses
  • Contact support for higher limits if needed

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Integration examples

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Common use cases

Popular API implementations:
  • Customer notifications: Order updates, appointment reminders
  • Marketing automation: Promotional campaigns, follow-up sequences
  • Support workflows: Ticket notifications, status updates
  • CRM integration: Sync contacts and communication history

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Development resources

Getting started quickly:
  • Interactive API explorer in documentation
  • Code samples in multiple programming languages
  • Postman collection for testing
  • Community examples and templates
Explore pre-built integrations that complement API usage:
View all available integrations on our integrations page, including Salesforce, HubSpot, and Gong.