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.

Mattermost publishes 6 API contracts indexed on the APIs.io network, including WebSocket API, Channels API, Posts API, and 3 more. Tagged areas include Messaging, Collaboration, Team Chat, Open Source, and DevOps.

The Mattermost catalog on APIs.io includes 1 event-driven AsyncAPI specification and 1 Spectral governance ruleset.

Mattermost’s developer surface includes authentication, documentation, signup flow, pricing, engineering blog, and 9 more developer resources.

🌐 Visit website 📡 Profile data on GitHub

37.2/100 thin ▬ flat Agent 26/100 agent aware Front door AI 5/6 prominent Heartbeat 100/100 alive saas Full breakdown ↓
scored 2026-11-06 · rubric v0.27.0 · Show this score on your site →

1 published contract 1 MCP Servers

Messaging Collaboration Team Chat Open Source DevOps Self-Hosted Real-Time

Kin Score

Kin Score How this is scored →
scored 2026-11-06 · rubric v0.27.0

Composite quality — 37.2/100 · thin

Contract Quality 9.6 / 19

Developer Ergonomics 6.1 / 15

Access Clarity 4.7 / 15

Operational Transparency 1.3 / 10

Contract Governance 1.0 / 9

Discoverability 4.9 / 8

Regulatory Posture 3.4 / 15

Create-or-Update Ergonomics 0.0 / 10

Agent readiness — 26/100 · agent aware

Machine-Readable Contract 18 / 18

Agentic Access Contract 10 / 10

Documented Reversibility 0 / 6

MCP Server 12 / 12

Machine-Readable Auth 10 / 10

Idempotency 0 / 9

Stable Error Semantics 0 / 8

Request/Response Examples 0 / 7

Rate-Limit Signaling 0 / 7

Typed Event Surface 6 / 6

Agent Skills 0 / 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

Pagination 5 / 5

Distinct Operations 3 / 3

MCP Tool Quality 6 / 6

Regulatory Posture applies to this provider. Its tags matched the Horizontal (data, software, accessibility, platform) 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.

Create-or-Update Ergonomics applies to this provider. This API accepts writes, so it carries 10 points of the composite. It is scored from the published contracts themselves: whether a caller can create-or-update in one call, whether the write accepts a key the caller already holds, and whether the response says which branch ran. Without that, every write needs a search-and-branch in front of it, and the first time that check is skipped a duplicate record is created. Scored against the observed mean rather than raw — a provider at the catalog average is unchanged by this facet, not penalised by it.

The six quality facets above are damped to 75 points between them, because the conditional facet above carries the other 25. That is why each facet's contribution is shown against a damped maximum: raising a quality facet moves the composite by 75% of its nominal weight, not 100%. The full arithmetic is at apis.io/rating/.

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Agent readiness — checks not met, largest first (exact, from this profile):

Idempotency +9 pts — OpenAPI mutating operations declare an idempotency key — a header, a request-body property, or a named de-duplication token whose own description says so (verified); else common[].type matches /idempoten/i (documented)
Stable Error Semantics +8 pts — OpenAPI $refs a shared error schema across 4xx/5xx responses (verified), else common[].type includes ErrorCatalog / ErrorCodes / DeclineCodes
A2A Agent Card +8 pts — a2a/-a2a.yml manifest, graded on conformance.grade against A2A 1.0.0
Rate-Limit Signaling +7 pts — OpenAPI responses document X-RateLimit-* / RateLimit headers (verified), else a rate_limits artifact or RateLimits link (documented)
Request/Response Examples +7 pts — share of operations carrying request/response examples; else an Examples / Code Samples link
Registration Without a Human +6 pts — a `registration_endpoint` in the served RFC 8414 / OIDC discovery document

8 more unmet checks in the Agent Readiness table above.

Kin Score — facets with the most composite points still available (weight × headroom):

Access Clarity scores 31.6 — up to +13.7 composite points
Contract Quality scores 51.3 — up to +12.2 composite points
Developer Ergonomics scores 40.5 — up to +11.9 composite points

Each check links to what satisfies it. Publish the artifact, or tell us where it already lives, and the score moves on the next scoring run.

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 the provider profile at artifacts.apis.io/mattermost/apis.yml: open an issue on github.com/api-evangelist/mattermost to ask a question or point us at an artifact you publish. Submit an artifact on GitHub — free → Manage your own listing — the Influence plan, $499/mo →

Markets this provider is in provisional

The Kin Score Market layer reads a provider inside its market: its position, and how deep its integrations go. Depth is only comparable within a position. Provisional and unweighted: not part of the Kin Score or agent readiness.

Market	Position	Depth	Registered MCP server	Declares compatibility
Workplace Collaboration App Marketplaces	standard	41.6	-	1
Vulnerability Disclosure (CVE Numbering Authorities, FIRST member teams; CISA KEV exposure)	standard	41.6	-	1
Red Hat Certified Ecosystem (certified partner containers + certified OpenShift operators)	standard	41.6	-	1
Artifact Hub Cloud-Native Packages	standard	41.6	-	1
Matrix Protocol Ecosystem (Matrix.org Foundation directory)	standard	41.6	-	1

Registered MCP server and declares compatibility are report only — not weighted. Undeclared means we found nothing we can read, so there is no number: we never infer integrations.

Standards implemented 3

Standards this provider implements or carries. De facto ones are profiled and measured by the API Commons; formal ones come from the standards directory and are linked by the provider's own tags. The evidence column says how each claim was established — not that it was made.

Model Context Protocol (MCP)

measured — observed by APIs.io (documented)

OpenAPI

measured — observed by APIs.io (published)

AsyncAPI

measured — observed by APIs.io (published)

APIs 6

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 5

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

Mattermost REST Channels API

OPEN COLLECTION

Mattermost REST Channels Posts API

OPEN COLLECTION

Mattermost REST Channels Teams API

OPEN COLLECTION

Mattermost REST Channels Users API

OPEN COLLECTION

Mattermost REST API

OPEN COLLECTION

MCP Servers 1

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

MCP Server

MCP SERVER

Event Specifications 1

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...

ASYNCAPI

Spectral Rules 1

Spectral governance rulesets for linting and validating these APIs.

Mattermost — asyncapi rules

8 rules · 1 errors 7 warnings

SPECTRAL

Security Posture 4

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

Mattermost Authentication

http · 1 scheme

SECURITY

Mattermost Domain Security

TLSv1.3 · HSTS · DMARC

SECURITY

Mattermost Vulnerability Disclosure

security.txt · contact published

SECURITY

Mattermost Trust Center

SOC 2, ISO 27001, ISO 27017, ISO 27018, HIPAA, FedRAMP, GDPR

SECURITY

Agentic Access 1

Recommended x-agentic-access execution contracts for AI agents.

Mattermost Agentic Access

43 operations · 26 acting

AGENTIC

Resources

Get Started 2

Portal, sign-up, and the first successful call

DeveloperPortal

DeveloperPortal

Signup

Signup

Documentation 1

Reference material describing how the API behaves

Documentation

Documentation

Agent Surfaces 2

MCP servers, agent skills, and machine-readable catalogs

AgenticAccess

AgenticAccess

MCPServer

MCPServer

Build 1

SDKs, sample code, and the tooling you integrate with

GitHubOrganization

GitHubOrganization

Access & Security 4

Authentication, authorization, and security posture

TrustCenter

TrustCenter

VulnerabilityDisclosure

VulnerabilityDisclosure

DomainSecurity

DomainSecurity

Authentication

Authentication

Commercial 1

Pricing, plans, and the legal terms of use

Pricing

Pricing

Company 3

The organization behind the API

LinkedIn

Website

Website

Blog

Blog

Source (apis.yml)

aid: mattermost
name: Mattermost
description: 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.
type: Index
deliveryModel:
  model: saas
  open_source: false
  commercial: true
  callable_host: false
  label: Hosted service · you call their endpoint
  confidence: medium
  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: '2026-11-06'
  method: derived
image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/icons/mattermost.png
x-docs-platform: docusaurus
x-docs-platform-confidence: medium
x-docs-platform-checked: 2026-10-04
x-docs-hosting: aws-cloudfront
tags:
- Messaging
- Collaboration
- Team Chat
- Open Source
- DevOps
- Self-Hosted
- Real-Time
tags_raw:
- Messaging
- Collaboration
- Team Chat
- Open Source
- DevOps
- Self-Hosted
- Open-Source
- Real-Time
url: https://raw.githubusercontent.com/api-evangelist/mattermost/refs/heads/main/apis.yml
created: '2026-05-11'
modified: '2026-05-29'
specificationVersion: '0.23'
apis:
- aid: mattermost:rest-api
  name: Mattermost REST API
  description: REST API v4 for managing users, teams, channels, posts, threads, files, integrations, plugins, webhooks, slash
    commands, and OAuth applications. Authentication uses Personal Access Tokens or session tokens via Bearer authentication.
  humanURL: https://api.mattermost.com/
  baseURL: https://your-mattermost-server.com/api/v4
  tags:
  - Messaging
  - User
  - Team
  - Channels
  - Posts
  - Webhook
  - Integration
  tags_raw:
  - Messaging
  - Users
  - Teams
  - Channels
  - Posts
  - Webhooks
  - Integrations
  properties:
  - type: Documentation
    url: https://api.mattermost.com/
  - type: APIReference
    url: https://developers.mattermost.com/integrate/reference/rest-api/
  - type: OpenAPI Source
    url: https://github.com/mattermost/mattermost-api-reference
  - type: Developer Guide
    url: https://developers.mattermost.com/contribute/more-info/server/rest-api/
- aid: mattermost:websocket-api
  name: Mattermost WebSocket API
  description: Real-time WebSocket event stream for Mattermost v4. Clients connect to /api/v4/websocket, authenticate via
    cookie, Authorization header, or an authentication_challenge action, and receive event envelopes (event, data, broadcast,
    seq) covering posts, channels, users, teams, reactions, typing, status, threads, plugins, and more. Client actions user_typing,
    get_statuses, and get_statuses_by_ids are supported over the same socket.
  humanURL: https://developers.mattermost.com/api-documentation
  baseURL: wss://your-mattermost-server.com/api/v4/websocket
  tags:
  - WebSocket
  - Event
  - Real-Time
  - Messaging
  - AsyncAPI
  tags_raw:
  - WebSocket
  - Events
  - Real-Time
  - Messaging
  - AsyncAPI
  properties:
  - type: Documentation
    url: https://developers.mattermost.com/api-documentation
  - type: AsyncAPI
    url: https://raw.githubusercontent.com/api-evangelist/mattermost/refs/heads/main/asyncapi/mattermost-asyncapi.yml
  - type: APIReference
    url: https://developers.mattermost.com/integrate/reference/rest-api/
- aid: mattermost:mattermost-channels-api
  name: Mattermost Channels API
  description: The Channels API from Mattermost — 7 operation(s) for channels.
  humanURL: https://api.mattermost.com/
  baseURL: https://your-mattermost-server.com/api/v4
  tags:
  - Channels
  properties:
  - type: OpenAPI
    url: openapi/mattermost-channels-api-openapi.yml
- aid: mattermost:mattermost-posts-api
  name: Mattermost Posts API
  description: The Posts API from Mattermost — 9 operation(s) for posts.
  humanURL: https://api.mattermost.com/
  baseURL: https://your-mattermost-server.com/api/v4
  tags:
  - Posts
  properties:
  - type: OpenAPI
    url: openapi/mattermost-posts-api-openapi.yml
- aid: mattermost:mattermost-teams-api
  name: Mattermost Teams API
  description: The Teams API from Mattermost — 6 operation(s) for teams.
  humanURL: https://api.mattermost.com/
  baseURL: https://your-mattermost-server.com/api/v4
  tags:
  - Team
  tags_raw:
  - Teams
  properties:
  - type: OpenAPI
    url: openapi/mattermost-teams-api-openapi.yml
- aid: mattermost:mattermost-users-api
  name: Mattermost Users API
  description: The Users API from Mattermost — 8 operation(s) for users.
  humanURL: https://api.mattermost.com/
  baseURL: https://your-mattermost-server.com/api/v4
  tags:
  - User
  tags_raw:
  - Users
  properties:
  - type: OpenAPI
    url: openapi/mattermost-users-api-openapi.yml
common:
- type: AgenticAccess
  url: agentic-access/mattermost-agentic-access.yml
- type: TrustCenter
  url: security/mattermost-trust-center.yml
- type: VulnerabilityDisclosure
  url: security/mattermost-vulnerability-disclosure.yml
- type: DomainSecurity
  url: security/mattermost-domain-security.yml
- type: Authentication
  url: authentication/mattermost-authentication.yml
- type: LinkedIn
  url: https://www.linkedin.com/company/mattermost
- type: Website
  url: https://mattermost.com
- type: Documentation
  url: https://docs.mattermost.com
- type: DeveloperPortal
  url: https://developers.mattermost.com/
- type: GitHubOrganization
  url: https://github.com/mattermost
- type: Signup
  url: https://mattermost.com/sign-up/
- type: Pricing
  url: https://mattermost.com/pricing/
- name: MCP Server
  url: https://github.com/mattermost/mmctl-mcp
  type: MCPServer
- url: https://mattermost.com/blog/feed/
  type: Blog
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com

Mattermost API — frequently asked questions

Does Mattermost have an API?

Yes. APIs.io lists 6 APIs from Mattermost, including Mattermost REST API, Mattermost WebSocket API and Mattermost Channels API, and 3 more.

Is there an OpenAPI specification for the Mattermost API?

Yes. APIs.io indexes 4 OpenAPI specifications for Mattermost, each linked for download from this page.

How do I authenticate with the Mattermost API?

Mattermost uses bearer-token authentication (http · 1 scheme). The details are profiled on APIs.io as Mattermost Authentication.

Does Mattermost have an MCP server?

Yes. APIs.io lists 1 MCP server for Mattermost.

Is the Mattermost API ready for AI agents?

Mattermost has a Kin Score of 37.2 out of 100 (thin) and an Agent Readiness score of 25.7 (agent-aware), scored by API Evangelist on 2026-11-06.

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get_provider_evidenceHow each part of their score was established. Free — the basis for a claim should not sit behind it.
get_provider_ratingPRO — composite, band, trend and facet scores.
apis_io_searchSTART HERE — APIs, providers and tags for one query, each with its total.
resolveTurn a domain, URL or GitHub org into the provider it belongs to.
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