Mattermost API

Name: Mattermost 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.

Install Jentic One Beta

Connect the Mattermost API to your agent

Jentic One is a self-hosted execution layer for AI agents. It lets your agent call the Mattermost API, or any other public or private API you need. You set the rules, the agent never sees your credentials, and every call is logged.

Two steps, two machines. Install the instance in a safe environment, then register your agent from wherever it runs.

Step 1: Jentic One Host machine

# On the machine that will host your Jentic One instance:
curl -fsSL https://raw.githubusercontent.com/jentic/jentic-one/main/tools/install.sh | sh

Step 2: Agent machine

# On the machine where your agent runs (keep this separate from the instance):
curl -fsSL https://raw.githubusercontent.com/jentic/jentic-one/main/tools/install.sh | sh
jentic register       # connects your agent to your Jentic One instance

Jentic One is in public beta. The setup above keeps your agent separate from the instance, which is what you want before using real credentials: an agent running as the same OS user as Jentic One can read its stored keys directly. Just evaluating? A single local install is fine to start. See the secure deployment guide for the tiers.

Capabilities

What an agent can do with Mattermost 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

GET STARTED

Start building with Mattermost API

Explore with Jentic

View OpenAPI Document

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 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 Jentic?

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

Credential isolation

Your Mattermost personal access token is stored once, encrypted, by your own Jentic One instance and applied as the Authorization header at execution time. It never enters the agent's prompt, logs, or context.

Intent-based discovery

Agents search Jentic by intent such as 'post a message to a Mattermost channel' or 'list Mattermost teams', and Jentic returns the matching Mattermost operation with its input schema so the agent calls the right endpoint without browsing the reference docs.

Time to first call

FAQs

Specific to using Mattermost 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 with Jentic One, the self-hosted execution layer.

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 your Jentic One instance.

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`.

Can I limit what my agent is allowed to do with the Mattermost API?

Yes. Because you self-host Jentic One, your own rules decide which Mattermost operations and credentials the agent may use, and it calls only the operations you allow. You can restrict it to just what a task needs, such as listing teams and channels or fetching the current user, while withholding the ability to create posts. The post target travels in the request body rather than the URL path, so any operation you leave out, including POST /posts, stays unreachable to the agent.

Mattermost API

Connect the Mattermost API to your agent

Capabilities

Start building with Mattermost API

Use Cases

Key Endpoints

Why Jentic?

Related APIs

FAQs