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Mattermost MCP server

Open-source, self-hosted Slack alternative

Mattermost is not a separate install. One Activepieces MCP server exposes it alongside 760+ other apps, behind a single URL.

Start building See the Mattermost integration
Tools
2
Works with
Any MCP client
Auth
Custom auth
License
MIT, open source
Updated
September 2026

About the Mattermost MCP server

Connect Mattermost once in Activepieces and every action it ships becomes a tool your assistant can call, behind the same server URL as the rest of your apps. Your agent reaches Mattermost and 760+ other apps over a single connection, on our cloud or a self-hosted install.

Tools

Mattermost tools your AI can run

Once connected, your assistant can call any of these Mattermost actions by asking in plain language.

  • Send Message

    Send a message to a Mattermost channel

    2 fields

  • Custom API Call

    Make a custom API call to a specific endpoint

    10 fields

Give your assistant Mattermost

Connect Mattermost once and every tool above is callable from Claude, Cursor or any MCP client, behind the same server URL as 760+ other apps. Free to start.

Get your server URLTalk to sales

Mattermost MCP, answered.

No. That is the point of it. One Activepieces server exposes Mattermost alongside every other piece you connect, so your client keeps a single connection.

Yes. Activepieces is open source and free to start, and the MCP server is included on every plan, from the free cloud tier to any self-hosted deployment.

Connect Mattermost in Activepieces, enable the server under Settings → MCP Server, then paste your server URL into your client config. It authenticates over OAuth on first use.

It can call 2 tools, including Send Message, Custom API Call, and chain them with steps in other apps inside the same run.

Connections use OAuth2 with limited scopes and are stored under 256-bit encryption, with no API to read them back, so an agent gets scoped access rather than your keys.

Guides using Mattermost

10 Best Automated Workflow Tools (Open Source) in 2026 Automated workflow tools connect apps and automate tasks without manual work. Compare the 10 best open-source options for 2026.Mattermost automation Read our quick guide on Mattermost automation. Discover how it works, explore common use cases, and learn how Activepieces can help.

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