OpenPhone

OpenPhone (rebranded to Quo in 2026) is a business phone and customer communications platform that provides shared phone numbers, calling, SMS/MMS texting, AI call summaries and transcripts, contacts, conversations, and tasks for teams. Its public REST API lets developers programmatically send messages, list and retrieve calls with recordings and voicemails, manage contacts and custom fields, manage conversations and tasks, look up phone numbers and users, and subscribe to webhooks for message and call events. The API uses API-key authentication in the Authorization header, returns JSON over HTTPS at https://api.quo.com, uses cursor-based pagination, and is rate limited to 10 requests per second. OpenPhone was surfaced as a portfolio company of 500 Global and profiled into the API Evangelist network.

OpenPhone publishes 9 APIs on the APIs.io network, including Calls API, Contact Custom Fields API, Contacts API, and 6 more. Tagged areas include Company, Communications, Voice, SMS, and Messaging.

The OpenPhone catalog on APIs.io includes 1 event-driven AsyncAPI specification.

OpenPhone’s developer surface includes documentation, API reference, getting-started guide, authentication, pricing, support, signup flow, and 22 more developer resources.

🌐 Visit website 📡 Source on GitHub
55.0/100 developing ▬ flat Agent 61/100 agent native Full breakdown ↓
scored 2026-07-23 · rubric v0.5
AccessSelf serve
9 APIs 1 MCP Servers
CompanyCommunicationsVoiceSMSMessagingTelephonyBusiness PhoneCPaaSContact CenterWebhooks

Kin Score

Kin Score Kin Score How this is scored →
scored 2026-07-23 · rubric v0.5
Composite quality — 55.0/100 · developing
Contract Quality 16.8 / 25
Developer Ergonomics 13.0 / 20
Commercial Clarity 10.0 / 20
Operational Transparency 5.1 / 13
Governance 0.0 / 12
Discoverability 10.0 / 10
Agent readiness — 61/100 · agent native
Machine-Readable Contract 18 / 18
Agentic Access Contract 0 / 15
MCP Server 12 / 12
Machine-Readable Auth 10 / 10
Idempotency 0 / 9
Stable Error Semantics 8 / 8
Request/Response Examples 0 / 7
Rate-Limit Signaling 0 / 7
Typed Event Surface 6 / 6
Agent Skills 5 / 5
Well-Known Catalog 4 / 4
Consent & Bot Identity 0 / 3
Improve this rating by publishing the missing artifacts — every area above can be raised, and the full rubric is at apis.io/rating/. This rating is computed from github.com/api-evangelist/openphone: open an issue to ask a question, or submit a pull request to add artifacts. Want it done for you? Prioritized profiling — $2,500 →

APIs 9

Individual APIs this provider publishes, each with its own machine-readable definition.

OpenPhone Calls API

Operations related to calls

OpenPhone Contact Custom Fields API

The Contact Custom Fields API from OpenPhone — 1 operation(s) for contact custom fields.

OpenPhone Contacts API

Operations related to contacts

OpenPhone Conversations API

Operations related to conversations

OpenPhone Messages API

Operations related to text messages

OpenPhone Phone Numbers API

Operations related to phone numbers

OpenPhone Tasks API

The Tasks API from OpenPhone — 10 operation(s) for tasks.

OpenPhone Users API

Operations related to users

OpenPhone Webhooks API

Operations related to webhooks

Scroll for all 9

MCP Servers 1

Model Context Protocol servers that expose these APIs to AI agents.

openphone-mcp.yml

MCP SERVER

Event Specifications 1

AsyncAPI definitions for this provider's event-driven and streaming APIs.

Openphone Webhooks

ASYNCAPI

Security Posture 3

Authentication, domain security, vulnerability disclosure, and trust-center signals.

Openphone Authentication

apiKey · 1 scheme

SECURITY

Openphone Domain Security

TLSv1.3 · DMARC

SECURITY

Openphone Trust Center

SOC 2, HIPAA, GDPR

SECURITY

Resources

Get Started 4

Portal, sign-up, and the first successful call

DeveloperPortal
DeveloperPortal
 GettingStarted
GettingStarted
 SignUp
SignUp
 Login
Login

Documentation 2

Reference material describing how the API behaves

Documentation
Documentation
 APIReference
APIReference

Agent Surfaces 4

MCP servers, agent skills, and machine-readable catalogs

MCPServer
MCPServer
 WellKnown
WellKnown
 LLMsTxt
LLMsTxt
 AgentSkill
AgentSkill

Design & Contract 6

Pagination, idempotency, versioning, errors, and events

Lifecycle
Lifecycle
 Conventions
Conventions
 ErrorCatalog
ErrorCatalog
 Conformance
Conformance
 DataModel
DataModel
 Webhooks
Webhooks

Build 1

SDKs, sample code, and the tooling you integrate with

Packages
Packages

Access & Security 4

Authentication, authorization, and security posture

TrustCenter
TrustCenter
 DomainSecurity
DomainSecurity
 Authentication
Authentication
 Compliance
Compliance

Operate 4

Status, limits, changes, and where to get help

Support
Support
 StatusPage
StatusPage
 ChangeLog
ChangeLog
 ChangeLog
ChangeLog

Commercial 2

Pricing, plans, and the legal terms of use

Pricing
Pricing
 TermsOfService
TermsOfService

Company 1

The organization behind the API

Website
Website

Other 1

Properties that don't map to a standard resource type

Overlay
Overlay

Source (apis.yml)

apis.yml Raw ↑ 
aid: openphone
name: OpenPhone
description: OpenPhone (rebranded to Quo in 2026) is a business phone and customer communications platform that provides shared
  phone numbers, calling, SMS/MMS texting, AI call summaries and transcripts, contacts, conversations, and tasks for teams.
  Its public REST API lets developers programmatically send messages, list and retrieve calls with recordings and voicemails,
  manage contacts and custom fields, manage conversations and tasks, look up phone numbers and users, and subscribe to webhooks
  for message and call events. The API uses API-key authentication in the Authorization header, returns JSON over HTTPS at
  https://api.quo.com, uses cursor-based pagination, and is rate limited to 10 requests per second. OpenPhone was surfaced
  as a portfolio company of 500 Global and profiled into the API Evangelist network.
url: https://raw.githubusercontent.com/api-evangelist/openphone/refs/heads/main/apis.yml
x-type: company
x-source: vc-portfolio
x-backed-by:
- 500-global
x-tier: profiled
x-tier-reason: has-public-api
x-rebrand:
  from: OpenPhone
  to: Quo
  note: openphone.com and api.openphone.com redirect to quo.com and api.quo.com
accessModel:
  pricing: unknown
  onboarding: self-serve
  trial: false
  try_now: false
  public: false
  label: Self-serve signup
  confidence: medium
  source:
  - authentication
  generated: '2026-07-22'
  method: derived
specificationVersion: '0.20'
created: '2026-07-17'
modified: '2026-07-20'
x-enrichment:
  date: '2026-07-20'
  status: enriched
  artifacts_added: 17
  pass: local-v1
tags:
- Company
- Communications
- Voice
- SMS
- Messaging
- Telephony
- Business Phone
- CPaaS
- Contact Center
- Webhooks
image: https://www.quo.com/favicon.ico
apis:
- aid: openphone:openphone-calls-api
  name: OpenPhone Calls API
  description: Operations related to calls
  humanURL: https://www.quo.com/docs/mdx/api-reference/introduction
  baseURL: https://api.quo.com
  tags:
  - Calls
  properties:
  - type: OpenAPI
    url: openapi/openphone-calls-api-openapi.yml
- aid: openphone:openphone-contact-custom-fields-api
  name: OpenPhone Contact Custom Fields API
  description: The Contact Custom Fields API from OpenPhone — 1 operation(s) for contact custom fields.
  humanURL: https://www.quo.com/docs/mdx/api-reference/introduction
  baseURL: https://api.quo.com
  tags:
  - Contact Custom Fields
  properties:
  - type: OpenAPI
    url: openapi/openphone-contact-custom-fields-api-openapi.yml
- aid: openphone:openphone-contacts-api
  name: OpenPhone Contacts API
  description: Operations related to contacts
  humanURL: https://www.quo.com/docs/mdx/api-reference/introduction
  baseURL: https://api.quo.com
  tags:
  - Contacts
  properties:
  - type: OpenAPI
    url: openapi/openphone-contacts-api-openapi.yml
- aid: openphone:openphone-conversations-api
  name: OpenPhone Conversations API
  description: Operations related to conversations
  humanURL: https://www.quo.com/docs/mdx/api-reference/introduction
  baseURL: https://api.quo.com
  tags:
  - Conversations
  properties:
  - type: OpenAPI
    url: openapi/openphone-conversations-api-openapi.yml
- aid: openphone:openphone-messages-api
  name: OpenPhone Messages API
  description: Operations related to text messages
  humanURL: https://www.quo.com/docs/mdx/api-reference/introduction
  baseURL: https://api.quo.com
  tags:
  - Messages
  properties:
  - type: OpenAPI
    url: openapi/openphone-messages-api-openapi.yml
- aid: openphone:openphone-phone-numbers-api
  name: OpenPhone Phone Numbers API
  description: Operations related to phone numbers
  humanURL: https://www.quo.com/docs/mdx/api-reference/introduction
  baseURL: https://api.quo.com
  tags:
  - Phone Numbers
  properties:
  - type: OpenAPI
    url: openapi/openphone-phone-numbers-api-openapi.yml
- aid: openphone:openphone-tasks-api
  name: OpenPhone Tasks API
  description: The Tasks API from OpenPhone — 10 operation(s) for tasks.
  humanURL: https://www.quo.com/docs/mdx/api-reference/introduction
  baseURL: https://api.quo.com
  tags:
  - Tasks
  properties:
  - type: OpenAPI
    url: openapi/openphone-tasks-api-openapi.yml
- aid: openphone:openphone-users-api
  name: OpenPhone Users API
  description: Operations related to users
  humanURL: https://www.quo.com/docs/mdx/api-reference/introduction
  baseURL: https://api.quo.com
  tags:
  - Users
  properties:
  - type: OpenAPI
    url: openapi/openphone-users-api-openapi.yml
- aid: openphone:openphone-webhooks-api
  name: OpenPhone Webhooks API
  description: Operations related to webhooks
  humanURL: https://www.quo.com/docs/mdx/api-reference/introduction
  baseURL: https://api.quo.com
  tags:
  - Webhooks
  properties:
  - type: OpenAPI
    url: openapi/openphone-webhooks-api-openapi.yml
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
- FN: APIs.json
  email: info@apis.io
common:
- type: TrustCenter
  url: security/openphone-trust-center.yml
- type: DomainSecurity
  url: security/openphone-domain-security.yml
- type: Website
  url: https://www.quo.com
- type: DeveloperPortal
  url: https://www.quo.com/docs
- type: Documentation
  url: https://www.quo.com/docs/mdx/api-reference/introduction
- type: APIReference
  url: https://www.quo.com/docs/mdx/api-reference/introduction
- type: GettingStarted
  url: https://www.quo.com/docs/mdx/api-reference/send-your-first-message
- type: Authentication
  url: authentication/openphone-authentication.yml
- type: Pricing
  url: https://www.quo.com/docs/mdx/pricing-support/pricing-overview
- type: Support
  url: https://support.quo.com/
- type: TermsOfService
  url: https://www.quo.com/terms
- type: SignUp
  url: https://my.openphone.com/signup
- type: Login
  url: https://my.openphone.com/
- type: StatusPage
  url: https://status.openphone.com
- type: ChangeLog
  url: https://www.quo.com/docs/mdx/api-reference/changelog
- type: ChangeLog
  url: changelog/openphone-changelog.yml
- type: Compliance
  url: https://www.quo.com/security
- type: Lifecycle
  url: lifecycle/openphone-lifecycle.yml
- type: Conventions
  url: conventions/openphone-conventions.yml
- type: ErrorCatalog
  url: errors/openphone-problem-types.yml
- type: Conformance
  url: conformance/openphone-conformance.yml
- type: DataModel
  url: data-model/openphone-data-model.yml
- type: Webhooks
  url: asyncapi/openphone-webhooks.yml
- type: MCPServer
  url: mcp/openphone-mcp.yml
- type: WellKnown
  url: well-known/openphone-well-known.yml
- type: Overlay
  url: overlays/openphone-openapi-overlay.yaml
- type: Packages
  url: packages/openphone-packages.yml
- type: LLMsTxt
  url: llms/openphone-llms.txt
- type: AgentSkill
  url: skills/_index.yml