Migration guide

How to migrate from Slack to Mattermost

Chat message history is the hardest thing to migrate between platforms — most teams migrate chat "going forward" and leave the old history as read-only reference.

1. 1

   Request a data export from Slack

   On paid plans, Slack usually lets you export the full history (messages, channels, files) as an administrative export, typically in JSON format.

2. 2

   Use Mattermost's import tool

   Tools like Mattermost or Rocket.Chat include command-line utilities to import Slack exports directly, preserving channels and threads where possible.

3. 3

   Recreate integrations and bots

   Webhooks, bots and connected apps don't migrate — you'll need to reconfigure every integration (CI/CD, alerts, etc.) to point at Mattermost.

4. 4

   Announce the switch with overlap

   Keep both platforms active for 1-2 weeks and pin a message in the old channels pointing to the new space, to minimize lost messages during the transition.

These steps are a general guideline — the exact export menu can vary depending on Slack's plan and version.