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ActionMattermostUpdated June 2026

How do I post to a Mattermost channel?

Short answer: You can send mattermost channel message in Mattermost by hand from its own interface, but it won’t repeat itself. On TinyCommand, add the Mattermost Send Mattermost Channel Message action to a workflow, map its 3 inputs from any upstream app, and it runs automatically every time the trigger fires. No code, and a free tier to start.

Send Mattermost Channel Message in Mattermost — start free All 7 Mattermost actions
Send Mattermost Channel Message in Mattermost — start free
Inputs

The fields this action accepts.

Every field can be mapped from an upstream trigger, AI step, table row, or hard-coded literal.

FieldTypeRequiredDescription
Channel ID
channel_id
stringRequiredChannel ID. Example: abcdef1234567890
Message
message
stringRequiredMessage text (supports Markdown)
Thread Root ID
root_id
stringOptionalPost ID to reply to (creates a threaded reply)
Sample request
{
  "channel_id": "e.g. abcdef1234567890",
  "message": "e.g. Build #42 deployed successfully :white_check_mark:",
  "root_id": "e.g. post123abc"
}
Returns
{
  "id": "post123",
  "message": "Build deployed!",
  "create_at": 1700000000000,
  "channel_id": "abcdef123"
}

Use these fields in downstream nodes for routing, logging, or error handling.

Triggered by

Apps that pair well as the trigger for Send Mattermost Channel Message.

Any of these apps can fire this action as part of a workflow.

Gmail → Mattermost
1 Gmail triggers
Slack → Mattermost
13 Slack triggers
Google Sheets → Mattermost
2 Google Sheets triggers
HubSpot → Mattermost
18 HubSpot triggers
FAQ

Questions about Send Mattermost Channel Message.

What does the Send Mattermost Channel Message action do in Mattermost?
Posts a message to a specific channel with optional attachments (Slack-attachment-style cards). The base hook for "external event → post to team channel" workflows.
What inputs does Send Mattermost Channel Message require?
Required: Channel ID, Message. Every input accepts a static value or a variable from any upstream node in your workflow.
Can I use dynamic inputs from earlier workflow nodes?
Yes. Any field on this action can pull values from upstream nodes, whether that's a form response, a trigger payload, an AI output, or a lookup result.
What happens if Mattermost returns an error?
The workflow pauses on the failed node, the error message is captured in the run log, and you can retry the run with one click. Auto-retry policies are configurable per workflow with exponential backoff up to 5 attempts.
Does Send Mattermost Channel Message support batch operations?
Yes. Run Send Mattermost Channel Message inside a Loop node to process arrays. TinyCommand handles Mattermost's rate limits automatically so you don't have to throttle manually.
More actions

Other Mattermost actions.

Action
Get Mattermost User
Returns a user by ID with profile and team memberships. Useful for resolving user IDs to readable identity in downstream notifications.
Action
List Mattermost Channels
Returns channels in a team that the connected user can see. Useful for channel inventory and for resolving channel IDs at workflow setup.
Action
List Mattermost Teams
Returns teams the connected user is a member of. The base lookup for multi-team workspaces.
Action
List Mattermost Users
Returns users in a team or workspace. Useful for "ping every team member" fan-out workflows or for user directory sync.
Action
Search Mattermost Posts
Full-text search with channel and date filters. For "find posts mentioning X" archive-search workflows.
Action
Send Mattermost DM
Sends a 1:1 or group DM by passing user IDs. Auto-creates the DM channel if needed. For "alert specific person" notification patterns.
Send Mattermost Channel Message in Mattermost — start free