Mattermost

Manage channels, messages, reactions, and users on Mattermost

Overview

The Mattermost tool interacts with a self-hosted Mattermost server via its REST API v4. It supports four resources: Channel (create, delete, addUser, members, restore, search, statistics), Message (post with optional file attachments and rich attachments, delete, postEphemeral), Reaction (create, delete, getAll), and User (create, deactivate, getAll, getByEmail, getById, invite). The message:post operation supports binary file uploads.

Category: Communication
Tool Name: mattermost
Version: 1

Appearance: Icon: si-mattermost | Color: #0058CC

Node Type

Action (Binary) — handles file/binary data operations

Input / Output

Direction	Port(s)
Input	Input
Output	Output, Error

Credentials

This tool requires Mattermost API credentials. See the Credentials Guide for setup instructions.

Resources

Resource	Value
Channel	channel
Message	message
Reaction	reaction
User	user

Operations

Operation	Value	Description
Add User	addUser	Add a user to a channel
Create	create	Create a new channel
Delete	delete	Soft-delete a channel
Members	members	Get members of a channel
Restore	restore	Restore a soft-deleted channel
Search	search	Search for channels in a team
Statistics	statistics	Get statistics for a channel
Delete	delete	Soft-delete a post
Post	post	Post a message into a channel
Post Ephemeral	postEphemeral	Post an ephemeral message visible to one user
Create	create	Add a reaction to a post
Delete	delete	Remove a reaction from a post
Get Many	getAll	Get all reactions for a post
Create	create	Create a new user
Deactivate	deactivate	Deactivate a user
Get By Email	getByEmail	Get a user by email
Get By ID	getById	Get users by their IDs
Get Many	getAll	Get many users
Invite	invite	Invite users to a team by email

The operation list is scoped to the resource you pick, which is why create, delete and getAll each appear more than once.

Parameters

Channel: Add User

Parameter	Type	Required	Default	Description
Channel ID	string	Yes	—	The ID of the channel to add the user to. Supports expressions.
User ID	string	Yes	—	The ID of the user to add to the channel. Supports expressions like {{ $json.userId }}.

Channel: Create

Parameter	Type	Required	Default	Description
Team ID	string	Yes	—	The ID of the team to create the channel in. Find in Mattermost team settings. Supports expressions.
Display Name	string	Yes	—	The non-unique display name for the channel (e.g. “Announcements”). Supports expressions.
Channel Name	string	Yes	—	The unique URL-safe handle for the channel (e.g. “announcements”). Supports expressions.
Type	options	No	public	The visibility of the channel.
				Options: public, private

Channel: Delete

Parameter	Type	Required	Default	Description
Channel ID	string	Yes	—	The ID of the channel. Supports expressions.

Channel: Members

Parameter	Type	Required	Default	Description
Team ID	string	Yes	—	The ID of the team (used for channel filtering). Supports expressions.
Channel ID	string	Yes	—	The ID of the channel to get members for. Supports expressions.
Resolve Data	boolean	No	true	Whether to resolve full user objects instead of just membership stubs.
Return All	boolean	No	true	Whether to return all results or only up to a given limit.
Limit	number	No	100	Max number of results to return. Accepts 1–100. (shown when Return All is false)

Channel: Restore

Parameter	Type	Required	Default	Description
Channel ID	string	Yes	—	The ID of the channel. Supports expressions.

Channel: Search

Parameter	Type	Required	Default	Description
Team ID	string	Yes	—	The ID of the team to search channels in. Supports expressions.
Search Term	string	Yes	—	The term to search for in channel names. Supports expressions.
Return All	boolean	No	false	Whether to return all results or only up to a given limit.
Limit	number	No	100	Max number of results to return. Accepts 1–100. (shown when Return All is false)

Channel: Statistics

Parameter	Type	Required	Default	Description
Channel ID	string	Yes	—	The ID of the channel. Supports expressions.

Message: Delete

Parameter	Type	Required	Default	Description
Post ID	string	Yes	—	The ID of the post to delete. Supports expressions.

Message: Post

Parameter	Type	Required	Default	Description
Channel ID	string	Yes	—	The ID of the channel to post the message in. Supports expressions.
Message	string	No	—	The message text to post. Supports expressions like {{ $json.text }}.
Attachments	json	No	[]	Rich message attachments as a JSON array. Each attachment can have: fallback, color, pretext, text, author_name, author_link, author_icon, title, title_link, fields (array of {title, value, short}), image_url, thumb_url, footer, footer_icon, actions.
Other Options	collection	No	{}	Additional options for the post.
— Parent Post ID (Thread)	string	No	—	If set, the message will be a threaded reply to this parent post. Supports expressions.
Send Binary Data	boolean	No	false	Whether to upload a binary file along with the message.
Binary Property	string	No	data	Name of the binary property on the input item to upload as a file attachment. Names are case-sensitive — see the upstream node’s Binary Data panel for the exact names to use. (shown when Send Binary Data is true)

Message: Post Ephemeral

Parameter	Type	Required	Default	Description
User ID	string	Yes	—	The ID of the user to send the ephemeral message to. Supports expressions.
Channel ID	string	Yes	—	The ID of the channel to send the ephemeral message in. Supports expressions.
Message	string	No	—	The ephemeral message text. Supports expressions.

Reaction: Create

Parameter	Type	Required	Default	Description
User ID	string	Yes	—	The ID of the user adding the reaction. Supports expressions.
Post ID	string	Yes	—	The ID of the post to react to. Supports expressions.
Emoji Name	string	Yes	—	The emoji name without colons (e.g. “thumbsup”). Supports expressions.

Reaction: Delete

Parameter	Type	Required	Default	Description
User ID	string	Yes	—	The ID of the user whose reaction to remove. Supports expressions.
Post ID	string	Yes	—	The ID of the post. Supports expressions.
Emoji Name	string	Yes	—	The emoji name to remove (without colons). Supports expressions.

Reaction: Get Many

Parameter	Type	Required	Default	Description
Post ID	string	Yes	—	The ID of the post to get reactions for. Supports expressions.
Return All	boolean	No	true	Whether to return all reactions or limit the results.
Limit	number	No	100	Max number of reactions to return. Accepts 1–100. (shown when Return All is false)

User: Create

Parameter	Type	Required	Default	Description
Username	string	Yes	—	The username for the new user. Supports expressions.
Auth Service	options	No	email	The authentication provider for the new user.
				Options: email, gitlab, google, ldap, office365, saml
Email	string	No	—	The email address for the new user (required when auth service is email). Supports expressions. (shown when Auth Service is email)
Password	string	No	—	The password for the new user (required when auth service is email). (shown when Auth Service is email)
Auth Data	string	No	—	The external auth data for the user (required when auth service is not email). (hidden when Auth Service is email)
Additional Fields	collection	No	{}	Optional profile fields for the new user.
— First Name	string	No	—	The user’s given name.
— Last Name	string	No	—	The user’s family name.
— Locale	string	No	—	The user’s interface locale, e.g. en.
— Nickname	string	No	—	The user’s nickname.

User: Deactivate

Parameter	Type	Required	Default	Description
User ID	string	Yes	—	The ID of the user to deactivate. Supports expressions.

User: Get By Email

Parameter	Type	Required	Default	Description
Email	string	Yes	—	The email address to look up. Supports expressions like {{ $json.email }}.

User: Get By ID

Parameter	Type	Required	Default	Description
User IDs	string	Yes	—	Comma-separated list of user IDs to look up. Supports expressions.
Additional Fields	collection	No	{}	Optional filters for the lookup.
— Since	string	No	—	Only return users modified after this ISO datetime.

User: Get Many

Parameter	Type	Required	Default	Description
Return All	boolean	No	true	Whether to return all users or only up to a given limit.
Limit	number	No	100	Max number of users to return. Accepts 1–100. (shown when Return All is false)
Additional Fields	collection	No	{}	Optional scoping and ordering for the listing.
— In Team	string	No	—	Filter users by team ID.
— Not In Team	string	No	—	Exclude users in this team.
— In Channel	string	No	—	Filter users by channel ID.
— Not In Channel	string	No	—	Exclude users in this channel.
— Sort	options	No	username	Sort field. When sort is set, either “In Team” or “In Channel” must also be set.
				Options: createdAt (Created At), lastActivityAt (Last Activity At), status, username

User: Invite

Parameter	Type	Required	Default	Description
Team ID	string	Yes	—	The ID of the team to invite users to. Supports expressions.
Emails	string	Yes	—	Comma-separated list of email addresses to invite. Supports expressions.

All Operations

Parameter	Type	Required	Default	Description
Max Concurrency	number	No	10	Maximum number of items to process concurrently.

Output Data

The Mattermost API response is merged into the item JSON at the top level, so the fields the input item already carried pass through unchanged and binary data is forwarded.

Operations that return a single object — every channel operation except Members and Search, both message posts, message delete, reaction create and delete, user create, deactivate, get by email and invite — produce one output item per input item.

Operations that return a list fan out: one output item per element, each a copy of the input item’s JSON with one record’s fields merged on. Those are:

Operation	One item per
channel / members	Channel member (a full user object when Resolve Data is on, otherwise a membership record)
channel / search	Matching channel
reaction / getAll	Reaction on the post
user / getById	User found
user / getAll	User in the listing

No Split Out node is needed after those five. Limit caps how many items come out; Return All pages through everything the server has.

File uploads. With Send Binary Data on, the named binary property is uploaded to Mattermost and attached to the post in the same execution — there is no separate upload node.

Usage Examples

• Post a message to a Mattermost channel
• Upload a file to a Mattermost channel with a message
• Create a new Mattermost channel
• Get all members of a channel
• Add a reaction to a post
• Invite users to a team by email
• Search for channels in a team

Example Configuration

Create a public channel:

{
  "type": "mattermost",
  "parameters": {
    "resource": "channel",
    "operation": "create",
    "teamId": "team123",
    "displayName": "General Discussion",
    "channel": "general-discussion",
    "type": "public"
  }
}

Post a message with a file upload, as a threaded reply:

{
  "type": "mattermost",
  "parameters": {
    "resource": "message",
    "operation": "post",
    "channelId": "channel456",
    "message": "Here's the report you requested",
    "sendBinaryData": true,
    "binaryPropertyName": "attachment",
    "otherOptions": {
      "root_id": "{{ $json.parentPostId }}"
    }
  }
}

Create a user with email authentication:

{
  "type": "mattermost",
  "parameters": {
    "resource": "user",
    "operation": "create",
    "username": "john.doe",
    "authService": "email",
    "email": "john.doe@company.com",
    "password": "securepassword123",
    "additionalFields": {
      "first_name": "John",
      "last_name": "Doe",
      "nickname": "johndoe"
    }
  }
}

Create a user backed by LDAP instead:

{
  "type": "mattermost",
  "parameters": {
    "resource": "user",
    "operation": "create",
    "username": "jane.smith",
    "authService": "ldap",
    "authData": "jane.smith@ldap"
  }
}

Add a reaction to a post:

{
  "type": "mattermost",
  "parameters": {
    "resource": "reaction",
    "operation": "create",
    "userId": "user789",
    "postId": "post123",
    "emojiName": "thumbsup"
  }
}

Get channel members, capped at 50 and resolved to full user objects:

{
  "type": "mattermost",
  "parameters": {
    "resource": "channel",
    "operation": "members",
    "teamId": "team123",
    "channelId": "channel456",
    "resolveData": true,
    "returnAll": false,
    "limit": 50
  }
}

List every user in a team, sorted by username:

{
  "type": "mattermost",
  "parameters": {
    "resource": "user",
    "operation": "getAll",
    "returnAll": true,
    "additionalFields": {
      "inTeam": "team123",
      "sort": "username"
    }
  }
}

Error Handling

Mode	Behavior
stop	Halts workflow on first error
continue	Skips failed items, passes successful ones through
errorPort	Routes failed items to Error output port

Tips

Post messages (with file uploads), manage channels, reactions, and users on a Mattermost server.

Key Relationships

• authService: "email" requires email and password parameters
• authService other than “email” requires authData parameter
• sendBinaryData: true requires binaryPropertyName parameter
• returnAll: false enables the limit parameter
• Collection parameters use flat object structure without _default wrapper

Key Notes

• Channel Name is the URL handle, Display Name is the label. Channel Name must be unique and URL-safe; Display Name is what people see.
• Sort needs a scope. In User: Get Many, setting Sort also requires In Team or In Channel in the same Additional Fields collection.
• Delete is a soft delete for both channels and posts, and Channel: Restore brings a soft-deleted channel back.