# Mattermost

**Canonical:** https://apis.io/providers/mattermost/  
**Website:** https://mattermost.com  
**APIs profiled:** 6

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.

## Kin Score — 36.5 / 100 (thin)

Scored 2026-08-20 under rubric 0.12.0. Trend: flat (+0.0 from 36.5).

| Facet | Score |
|---|---|
| Discoverability | 74.1 |
| Contract Quality | 57.5 |
| Governance | 11.4 |
| Contract Governance | 11.4 |
| Operational Transparency | 2.6 |
| Developer Ergonomics | 33.3 |
| Commercial Clarity | 31.6 |
| Access Clarity | 31.6 |

## Agent readiness — 31.5 (agent-aware)

| Dimension | Value |
|---|---|
| Spec Presence | yes |
| Agentic Access | derived |
| Reversibility Documented | no |
| MCP Server | documented |
| Auth Clarity | yes |
| Idempotency | no |
| Error Semantics | no |
| OpenAPI Examples | no |
| Rate Limit Signal | no |
| Event Surface Described | derived |
| Agent Skills | no |
| Well Known Catalog | no |
| Consent Identity | no |
| Agent Card | no |
| Dry Run Mode | no |

## Access

Self-serve signup — onboarding: self-serve, pricing: unknown, trial: no (confidence: medium).

## APIs (6)

- **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.

## MCP servers (1)

- **MCP Server**

## Agentic access (1)

- **Mattermost Agentic Access** — 43 operations · 29 acting

## Security (4)

- **Mattermost Authentication** — http · 1 scheme
- **Mattermost Domain Security** — TLSv1.3 · HSTS · DMARC
- **Mattermost Vulnerability Disclosure** — security.txt · contact published
- **Mattermost Trust Center** — SOC 2, ISO 27001, ISO 27017, ISO 27018, HIPAA, FedRAMP, GDPR

## Tags

Messaging, Collaboration, Team Chat, Open-Source, DevOps, Self-Hosted

---

Profiled by [API Evangelist](https://apievangelist.com) and published on [APIs.io](https://apis.io/providers/mattermost/). Scores are computed from the provider's own public artifacts under a published rubric.