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 23 more developer resources.

🌐 Visit website 📡 Source on GitHub

52.8/100 developing ▬ flat Agent 29/100 agent ready saas Full breakdown ↓
scored 2026-09-06 · rubric v0.19.0

2 APIs

Company Communications Voice SMS Messaging TelephonyBusiness PhoneCPaaS Contact Center Webhook

Kin Score

Kin Score How this is scored →
scored 2026-09-06 · rubric v0.19.0

Composite quality — 52.8/100 · developing

Contract Quality 14.3 / 21

Developer Ergonomics 9.6 / 17

Access Clarity 7.4 / 17

Operational Transparency 4.4 / 11

Contract Governance 1.9 / 10

Discoverability 6.5 / 9

Regulatory Posture 5.4 / 15

Agent readiness — 29/100 · agent ready

Machine-Readable Contract 18 / 18

Agentic Access Contract 0 / 10

Documented Reversibility 0 / 6

MCP Server 0 / 12

Machine-Readable Auth 10 / 10

Idempotency 0 / 9

Stable Error Semantics 8 / 8

Request/Response Examples 7 / 7

Rate-Limit Signaling 0 / 7

Typed Event Surface 6 / 6

Agent Skills 5 / 5

Well-Known Catalog 0 / 4

Consent & Bot Identity 0 / 3

A2A Agent Card 0 / 8

Dry-Run / Simulate Mode 0 / 4

Delegated User Identity 0 / 6

Protected Resource Metadata 0 / 5

Registration Without a Human 0 / 6

Agentic Commerce Well-Known Document 0 / 5

Regulatory Posture applies to this provider. Its tags matched the Telecommunications regime, so Regulatory Posture carries 15 points of the composite. If this regime is wrong for your business, say so on your provider repo — the applicability map is public and we will correct it.

The six quality facets above are damped to 85 points between them, because the conditional facet above carries the other 15. That is why each facet's contribution is shown against a damped maximum: raising a quality facet moves the composite by 85% of its nominal weight, not 100%. The full arithmetic is at apis.io/rating/.

Improve this rating by publishing the missing artifacts — every area above can be raised, and the full rubric is at apis.io/rating/. Every facet and dimension name above is a link: it opens that measurement's own page — what it means, the exact checks that feed it, how the whole catalog distributes on it, and the providers at the top of it. 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. Submit an artifact on GitHub — free → Manage your own listing — the Influence plan, $499/mo →

APIs 9

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

Open Collections 10

Open, tool-agnostic API collections (OpenAPI-derived and Bruno).

Get Started 4

Portal, sign-up, and the first successful call

DeveloperPortal

DeveloperPortal

GettingStarted

GettingStarted

SignUp

SignUp

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

X-MCPServerCandidate

WellKnown

LLMsTxt

AgentSkill

Design & Contract 6

Pagination, idempotency, versioning, errors, and events

Lifecycle

Conventions

ErrorCatalog

Conformance

DataModel

Webhooks

Build 1

SDKs, sample code, and the tooling you integrate with

Packages

Packages

Access & Security 4

Authentication, authorization, and security posture

TrustCenter

DomainSecurity

Authentication

Compliance

Operate 4

Status, limits, changes, and where to get help

Support

StatusPage

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 2

Properties that don't map to a standard resource type

CapabilityMap

CapabilityMap

Overlay

Overlay

Source (apis.yml)

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
deliveryModel:
  model: saas
  open_source: false
  commercial: true
  callable_host: true
  label: Hosted service · you call their endpoint
  confidence: high
  source:
  - openapi
  - pricing
  generated: '2026-08-28'
  method: derived
accessModel:
  pricing: unknown
  onboarding: unknown
  trial: false
  try_now: false
  public: false
  label: Unknown
  confidence: low
  source:
  - authentication
  - security
  generated: '2026-09-03'
  method: derived
specificationVersion: '0.23'
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
- Webhook
tags_raw:
- 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:
  - Message
  tags_raw:
  - 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:
  - Task
  tags_raw:
  - 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:
  - User
  tags_raw:
  - 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:
  - Webhook
  tags_raw:
  - 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: CapabilityMap
  url: capabilities/openphone-capability-edges.yml
  name: OpenPhone Business Capability Map
- 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: X-MCPServerCandidate
  url: mcp/openphone-mcp.yml
  note: 'Renamed from MCPServer 2026-09-03 (roadmap#247): the manifest self-describes as status: candidate — a tool list derived
    from the published API contracts, not an existing server. The scorer already read the manifest and reported mcp_server
    correctly; the MCPServer type was crediting the artifact-type surfaces with a server that does not exist.'
- 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

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