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How to Switch from Slack to Mattermost

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Slack
m
mattermost
Medium 60 minutes Updated 21 January 2026 Privacy Registry Team

Introduction

This guide will help you switch from Slack to Mattermost, an open-source, self-hosted team collaboration platform. Mattermost provides a Slack-like experience with full control over your data.

Why switch?

  • Slack stores all messages on their servers
  • Data subject to US jurisdiction
  • No self-hosting option
  • Rising costs for growing teams
  • Limited control over data retention

Why Mattermost?

  • Self-host on your own infrastructure
  • Open source and auditable
  • Full data control and sovereignty
  • One-time or lower ongoing costs
  • Slack-like familiar interface
  • Built-in compliance features

Prerequisites

  • Slack workspace admin access
  • Server for Mattermost (self-hosted or cloud)
  • Docker or direct installation capability
  • About 60 minutes for setup and migration
  • Team coordination

Info: Mattermost offers both self-hosted (free/paid) and cloud-hosted options. Self-hosting gives maximum control.

Step 1: Set up your Mattermost server

# Clone Mattermost Docker setup
git clone https://github.com/mattermost/docker
cd docker

# Copy and configure environment
cp env.example .env
# Edit .env with your settings

# Start Mattermost
docker compose up -d

Option B: Cloud hosted (Easiest)

  1. Visit mattermost.com/sign-up
  2. Create a cloud workspace
  3. Choose your plan
  4. Workspace is ready immediately

Option C: Direct installation

  1. Download Mattermost from mattermost.com/download
  2. Follow the installation guide for your OS
  3. Configure database (PostgreSQL recommended)
  4. Set up reverse proxy with SSL

Tip: For production, use PostgreSQL and set up proper backups from the start.

Step 2: Configure your Mattermost workspace

  1. Access the System Console (admin panel)
  2. Configure key settings:
    • Site URL
    • Email/SMTP settings
    • Authentication method
    • File storage location
  3. Create your team
  4. Set up channels to match Slack structure

Step 3: Export data from Slack

Mattermost can import Slack exports:

  1. In Slack, go to Administration > Settings & Administration
  2. Click “Import/Export Data”
  3. Request a workspace export
  4. Download the export ZIP file

Warning: Free Slack plans have limited export options. Check what data is included.

Step 4: Import Slack data to Mattermost

Using the Mattermost Bulk Import:

  1. Log into Mattermost System Console
  2. Go to Import > Slack Import
  3. Upload your Slack export ZIP
  4. Map Slack channels to Mattermost channels
  5. Start the import process
  6. Review import logs for any issues

Imported data includes:

  • Public channel messages
  • Direct messages (depending on Slack plan)
  • User information
  • File attachments

Tip: Run a test import first with a subset of channels to verify everything works.

Step 5: Invite your team

Create user accounts

Option A: Manual invitation

  1. Go to Team Settings > Invite People
  2. Generate invite link or send email invites

Option B: SSO/LDAP (Enterprise)

  1. Configure SSO in System Console
  2. Users log in with existing credentials

Option C: Bulk import

  1. Prepare CSV with user details
  2. Use CLI to bulk import users

Step 6: Set up integrations

Mattermost supports many integrations:

  1. Incoming Webhooks: Receive notifications from other services
  2. Outgoing Webhooks: Trigger actions on messages
  3. Slash Commands: Custom commands like Slack
  4. Plugins: GitHub, Jira, Zoom, and many more

Install plugins from System Console > Plugins.

Tips & Gotchas

Warning: Slack emoji names may differ. Custom emoji need to be re-uploaded to Mattermost.

  • File storage: Configure S3 or MinIO for scalable file storage
  • Search: Mattermost uses Bleve or Elasticsearch for search
  • Mobile apps: iOS and Android apps available
  • Desktop app: Available for all platforms
  • Threads: Mattermost supports threaded conversations
  • Data retention: Configure retention policies in Enterprise edition

What’s Next?

After completing this guide:

  1. Configure notifications: Set up email and push notifications
  2. Install plugins: Add integrations your team needs
  3. Set up bots: Automate workflows
  4. Configure backup: Ensure database and files are backed up
  5. Train your team: The interface is similar to Slack
  6. Decommission Slack: After successful migration

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