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.
Real signal across most facets with visible, nameable gaps — the contract exists but is thin, or the portal is good while governance and commercial terms are absent.
API Evangelist profiles OpenPhone the way a machine reads it — 14 machine-readable artifacts across 9 APIs, pulled from the provider's own public surface and indexed so a developer, an analyst, or an AI agent can evaluate it against every other provider on the network.
Every provider in the network is reduced to the same set of machine-readable artifacts — OpenAPI contracts, event specifications, GraphQL schemas, runnable collections, pricing and rate-limit signals, security posture, OAuth scopes, and the agent surfaces (MCP servers and skills) that let software drive the API on its own. We profile them because the interface is the part of a company you can actually inspect: it is a truer signal of what a provider does than any marketing page. From those artifacts we compute the Kin Score — OpenPhone scores 55.0/100 (developing), with a separate agent-readiness read of 61/100 (agent native). The full breakdown is below, followed by every artifact we hold — each card links through to its machine-readable definition on apis.io.
Kin Score
This is the API Evangelist rating — a single, repeatable read computed from the artifacts on this page. Green fill is points earned; the red track is points possible, so every bar shows earned-versus-possible at a glance.
Kin Score
How this is scored →scored 2026-07-27 · rubric v0.5
How we profile OpenPhone
Each block below is one kind of artifact we hold for OpenPhone. For each we say what it is and why it earns a place in the profile, then list every one we've indexed — capped at two rows, scroll within the panel for the rest.
APIs 9
Each API is captured as its own OpenAPI definition — every operation, parameter, and response. This is the single most useful machine-readable description of what an API does, and it's what lets us score, lint, mock, and generate against it without asking the provider for anything.
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 within the panel for all 9 ·
MCP Servers 1
Model Context Protocol servers expose these APIs directly to AI agents. We profile them because agent-native access is the fastest-growing way this provider's capabilities actually get used.
Model Context Protocol servers that expose these APIs to AI agents.
openphone-mcp.yml
MCP SERVEREvent Specifications 1
Not every API is request/response. AsyncAPI describes the event-driven and streaming side — the webhooks and channels — so the asynchronous half of the interface is documented the same way the synchronous half is.
AsyncAPI definitions for this provider's event-driven and streaming APIs.
Openphone Webhooks
ASYNCAPISecurity Posture 3
Authentication, domain security, vulnerability disclosure, and trust-center signals — the evidence that a provider takes security seriously enough to document it. We profile it because you can't govern what you can't see.
Authentication, domain security, vulnerability disclosure, and trust-center signals.
Resources
Every other property we hold for OpenPhone — documentation, portals, status pages, policies, and corporate surface — grouped by the job it does, following the integrator's arc from getting started to running in production.
Get Started 4
Portal, sign-up, and the first successful call
Documentation 2
Reference material describing how the API behaves
Agent Surfaces 4
MCP servers, agent skills, and machine-readable catalogs
Design & Contract 6
Pagination, idempotency, versioning, errors, and events
Build 1
SDKs, sample code, and the tooling you integrate with
Access & Security 4
Authentication, authorization, and security posture
Operate 4
Status, limits, changes, and where to get help
Commercial 2
Pricing, plans, and the legal terms of use
Company 1
The organization behind the API
Other 1
Properties that don't map to a standard resource type
← All providers · Data indexed from github.com/api-evangelist/openphone · machine-readable index on apis.io