OpenPhone Business Phone API

OpenPhone API for modern business phone system designed for startups and small teams. Enables programmatic access to calls, SMS/MMS messages, contacts, and voicemails. OpenPhone is popular with startups for its simplicity and integrations with Zapier, Salesforce, and HubSpot.

Evaluated Mar 07, 2026 (0d ago) vcurrent
Homepage ↗ Other openphone voip phone sms startup small-business team-phone
⚙ Agent Friendliness
58
/ 100
Can an agent use this?
🔒 Security
76
/ 100
Is it safe for agents?
⚡ Reliability
66
/ 100
Does it work consistently?

Score Breakdown

⚙ Agent Friendliness

MCP Quality
30
Documentation
68
Error Messages
65
Auth Simplicity
72
Rate Limits
62

🔒 Security

TLS Enforcement
90
Auth Strength
78
Scope Granularity
65
Dep. Hygiene
68
Secret Handling
78

Customer call and SMS data. SOC2 certified. US/Canada only. API key security required.

⚡ Reliability

Uptime/SLA
72
Version Stability
68
Breaking Changes
62
Error Recovery
62
AF Security Reliability

Best When

A startup or small team using OpenPhone wants AI agents to automate SMS follow-ups, log calls to CRM, and transcribe voicemails — without complex enterprise telephony setup.

Avoid When

You need enterprise-grade contact center features. OpenPhone is optimized for small teams. PRIVACY: Call recordings and SMS messages contain customer data.

Use Cases

  • Querying call and SMS history from small business communications agents
  • Sending automated SMS follow-ups from sales workflow automation agents
  • Retrieving voicemail transcriptions from customer service automation agents
  • Syncing OpenPhone contacts with CRM tools from sales pipeline agents

Not For

  • Large enterprise contact center operations (OpenPhone is SMB-focused)
  • High-volume A2P SMS campaigns (OpenPhone is for small team conversations)
  • Complex IVR and call routing requirements

Interface

REST API
Yes
GraphQL
No
gRPC
No
MCP Server
No
SDK
No
Webhooks
Yes

Authentication

Methods: api_key
OAuth: No Scopes: No

OpenPhone API key authentication. Keys generated in OpenPhone account settings. Webhook verification for incoming events.

Pricing

Model: freemium
Free tier: No
Requires CC: Yes

OpenPhone subscription required. API access included with Business plan and above.

Agent Metadata

Pagination
cursor
Idempotent
Partial
Retry Guidance
Not documented

Known Gotchas

  • PRIVACY: Call recordings and SMS messages are customer communication data
  • No public MCP server — REST API integration required
  • API only available on Business plan and above
  • US and Canada phone numbers only
  • SMS sending rate limits apply — batch messaging requires planning

Alternatives

Full Evaluation Report

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Scores are editorial opinions as of 2026-03-07.

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