Mattermost
Mattermost is an open-source collaboration platform for technical teams that combines secure team messaging, workflow automation, voice/video calling, and integrations as a self-hosted Slack alternative. The Mattermost REST API exposes full programmatic control over users, teams, channels, posts, files, integrations, plugins, and webhooks.
Limited machine-readable signal and partial portal coverage — documentation a human can read, but little a machine or agent can consume without scraping.
API Evangelist profiles Mattermost the way a machine reads it — 16 machine-readable artifacts across 6 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 — Mattermost scores 43.1/100 (thin), with a separate agent-readiness read of 59/100 (agent ready). 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 Mattermost
Each block below is one kind of artifact we hold for Mattermost. 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 6
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.
Mattermost REST API
REST API v4 for managing users, teams, channels, posts, threads, files, integrations, plugins, webhooks, slash commands, and OAuth applications. Authentication uses Personal Acc...
Mattermost WebSocket API
Real-time WebSocket event stream for Mattermost v4. Clients connect to /api/v4/websocket, authenticate via cookie, Authorization header, or an authentication_challenge action, a...
Mattermost Channels API
The Channels API from Mattermost — 7 operation(s) for channels.
Mattermost Posts API
The Posts API from Mattermost — 9 operation(s) for posts.
Mattermost Teams API
The Teams API from Mattermost — 6 operation(s) for teams.
Mattermost Users API
The Users API from Mattermost — 8 operation(s) for users.
Open Collections 1
Open, tool-agnostic collections carry the same runnable value as Postman without locking you to one client — the portable, forkable form of the same exercise.
Open, tool-agnostic API collections (OpenAPI-derived and Bruno).
Mattermost REST API
OPEN COLLECTIONMCP 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.
MCP Server
MCP SERVERGraphQL 1
Where a provider ships GraphQL, the schema is the contract. We profile it alongside the REST surface so the whole interface is legible in one place.
GraphQL schemas published by this provider.
Mattermost GraphQL Schema
Conceptual GraphQL schema for the [Mattermost](https://mattermost.com) open-source team messaging platform, derived from the [Mattermost REST API v4](https://api.mattermost.com/).
GRAPHQLEvent 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.
Mattermost WebSocket API
Mattermost's WebSocket API delivers real-time events from a Mattermost server to authenticated clients and accepts a small set of WebSocket actions for client-to-server interact...
ASYNCAPISpectral Rules 1
Governance rulesets we run against this provider's specs — the automated checks behind parts of the score. Profiling them makes the quality bar explicit and re-runnable, not a matter of opinion.
Mattermost API Rules
SPECTRALSecurity Posture 4
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.
Agentic Access 1
An x-agentic-access contract marks which operations are safe for an agent to run on its own and which need a human in the loop. It is the difference between an API an agent can use and one it can use safely.
Recommended x-agentic-access execution contracts for AI agents.
Resources
Every other property we hold for Mattermost — 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 2
Portal, sign-up, and the first successful call
Documentation 1
Reference material describing how the API behaves
Agent Surfaces 2
MCP servers, agent skills, and machine-readable catalogs
Build 1
SDKs, sample code, and the tooling you integrate with
Access & Security 4
Authentication, authorization, and security posture
Commercial 1
Pricing, plans, and the legal terms of use
Company 3
The organization behind the API
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