Mattermost API

Name: Mattermost API API
Brand: Mattermost API
Availability: InStock

★ Only Publicly Available OpenAPI DocumentCommunicationsChat Messagingbearer8 EndpointsREST

For Agents

Authenticate users, fetch team and channel context, and post messages on a self-hosted Mattermost server with bearer-token auth.

Quickstart

Get started with Mattermost API in minutes using your preferred integration method.

# Add to your MCP client config (Claude Desktop, Cursor, Windsurf)
{
  "jentic": {
    "url": "https://api.jentic.com/mcp",
    "auth": "oauth"
  }
}

# Then ask your agent:
"post message to mattermost channel"

# → Jentic returns the GET /events tool with parameter schema, agent executes.

Capabilities

What an agent can do with Mattermost API API.

Authenticate a user via login and obtain a session bearer token

Fetch the authenticated user's identity via the `me` endpoint

List teams and channels the authenticated user belongs to

Create posts in a Mattermost channel

Resolve user identity for downstream activity records

GET STARTED

Start building with Mattermost API API

Explore with Jentic

View OpenAPI Document

Use for: Log in to Mattermost with username and password and store the session token, Get the currently authenticated Mattermost user via the `me` endpoint, List all teams the user is a member of, Post a message to a Mattermost channel

Not supported: Does not handle WebSocket event streams, server administration, or plugin management — use for the v4 REST surface (auth, users, teams, channels, posts) only.

Jentic publishes the only available OpenAPI document for Mattermost API, keeping it validated and agent-ready.

Jentic publishes the only available OpenAPI specification for Mattermost API, keeping it validated and agent-ready. Mattermost is an open-source, self-hosted team-collaboration platform with HTTP and WebSocket APIs at `your-mattermost-url/api/v4`. The spec covers the core flows used by clients and bots: user authentication and identity, team and channel access, post creation, and basic file and preference operations. It is intended for developers building Mattermost integrations, internal bots, and AI agents that participate in Mattermost teams. Authentication uses bearer session tokens or personal access tokens.

Use Cases

Patterns agents use Mattermost API API for, with concrete tasks.

★ CI Status Bot

Engineering teams running self-hosted Mattermost want CI build statuses posted to a dedicated channel. The bot logs in once with a personal access token, fetches the right team and channel ID, and then creates posts whenever the CI pipeline emits a status. Posts typically include build URL, branch, and outcome.

Authenticate via `POST /users/login`, locate the channel id, then call `POST /posts` with the channel_id and the build summary message.

Identity-Aware Internal Tool

Internal admin tools running alongside Mattermost can use the chat session to identify the operator. The tool calls `GET /users/me` to confirm the logged-in user and uses the result to drive permissions in the tool itself, avoiding a separate auth system for internal-only utilities.

Call `GET /users/me` with the bearer token to retrieve the authenticated user's id, email, and role membership.

Team and Channel Discovery

Onboarding scripts that provision new bots or integrations need to enumerate teams and channels to find the correct destination. The `/teams` and `/channels` endpoints expose this listing, and a typical onboarding script caches the IDs locally so subsequent posts can skip the lookup step.

Call `GET /teams` followed by `GET /channels` to build a `{team_name → channel_ids}` map for the integration's config.

AI Agent in Mattermost

An AI agent that posts summaries or answers questions in a Mattermost channel can use Jentic to call the right operations on demand. Jentic stores the session or personal access token in the vault and exposes login, identity, and post operations via intent search, removing per-server auth boilerplate.

Search Jentic for 'post message to mattermost channel', load the `/posts` schema, and execute it with the channel_id and message body.

Key Endpoints

8 endpoints — jentic publishes the only available openapi specification for mattermost api, keeping it validated and agent-ready.

METHOD

PATH

DESCRIPTION

POST

/users/login

Authenticate and obtain a session token

GET

/users/me

Fetch the authenticated user

GET

/users

List users on the server

GET

/teams

List teams

GET

/channels

List channels

POST

/posts

Create a post in a channel

POST

/users/login

Authenticate and obtain a session token

GET

/users/me

Fetch the authenticated user

GET

/users

List users on the server

GET

/teams

List teams

GET

/channels

List channels

POST

/posts

Why though Jentic?

Three things that make agents converge on Jentic-routed access.

Credential isolation

Mattermost session and personal access tokens are stored encrypted in the Jentic vault (MAXsystem). Agents receive scoped session references and the `Authorization: Bearer ...` header is applied at execution time — raw tokens never enter the agent's context.

Intent-based discovery

Agents search by intent (e.g., 'post message to mattermost channel' or 'list mattermost teams') and Jentic returns the matching Mattermost operation with its input schema.

Time to first call

Direct Mattermost integration: 4-6 hours for login, token management, and post wiring. Through Jentic: under 30 minutes — search, load schema, execute.

Related APIs

Alternatives and complements available in the Jentic catalogue.

Alternative

Slack API

Slack is a hosted team-chat platform with a similar channel-and-post model.

Choose Slack when the team is on Slack's SaaS rather than running a self-hosted Mattermost server.

Alternative

Discord API

Discord offers community-focused chat with guilds, voice, and bot APIs.

Choose Discord when the audience is community-focused rather than enterprise team chat.

Alternative

Matrix Client-Server API

Matrix is an open, federated chat protocol with self-hostable homeservers.

Choose Matrix when federation across organisations matters more than the Mattermost product feature set.

Alternative

Zulip API

Zulip is an open-source team chat focused on threaded conversations.

Choose Zulip when topic-based threading is the differentiator versus Mattermost's channel model.

FAQs

Specific to using Mattermost API API through Jentic.

Why is there no official OpenAPI spec for Mattermost API?

Mattermost publishes its API documentation as a custom site rather than a single OpenAPI document. Jentic generates and maintains an OpenAPI specification so AI agents and developers can call the Mattermost API via structured tooling. It is validated against the live API and kept up to date. Get started at https://app.jentic.com/sign-up.

What authentication does the Mattermost API use?

Mattermost uses HTTP bearer tokens in the `Authorization: Bearer ...` header. Tokens are issued either by `POST /users/login` (session token) or as personal access tokens generated in the Mattermost UI. Through Jentic, both are stored encrypted in the MAXsystem vault.

Can I post a message to a channel with the Mattermost API?

Yes. `POST /posts` creates a new post in a channel. Provide the `channel_id` and `message` body in the JSON payload, plus an optional `root_id` to make the post a reply within an existing thread.

What are the rate limits for the Mattermost API?

Mattermost rate limits are configured per server by the admin and enforced via `X-Ratelimit-Limit`, `X-Ratelimit-Remaining`, and `X-Ratelimit-Reset` response headers. The default is 10 requests per second per user; on `429 Too Many Requests`, back off until the reset window elapses.

How do I send a Mattermost post through Jentic?

Run `pip install jentic`, then use Jentic's search with the query 'post message to mattermost channel'. Jentic loads the `/posts` operation schema and your agent executes it with the channel_id and message — Jentic injects the bearer token automatically.

Does the API work against a self-hosted Mattermost server?

Yes. The base URL is parameterised as `https://{serverUrl}/api/v4`, so the same operations work against the public Mattermost cloud, an internal enterprise install, or a developer's local instance running on `http://localhost:8065`.