Slack Bridge #

Based on mautrix-slack. Supports modern Slack workspaces (both free and paid plans). Channels become Matrix rooms, your full workspace becomes a Matrix space, and DMs / threads / reactions all sync bi-directionally.

Prerequisites #

Meldry plan: Pro or Business
A Slack account on the workspace you want to bridge
Workspace admin consent to install a Slack app — if you're not the admin, the bridge will still work with user-token auth, but some features (channel list sync, DM listing) are restricted

Enable the bridge #

Open Dashboard → Server → Bridges.
Find Slack and click Enable.
Wait ~10 seconds. The bridge bot appears at @slackbot:<your-name>.meldry.com.

Link your Slack account #

There are two ways to authenticate; pick one.

This uses your personal Slack user token — the same credential the Slack desktop/web app uses.

In Slack (web or desktop), open any workspace you want to bridge.
Open browser DevTools → Application → Local Storage → https://app.slack.com.
Find the entry localConfig_v2. Inside it, locate the token field for your workspace — it starts with xoxc-....
Also find the d cookie in Cookies → https://app.slack.com — starts with xoxd-....
In your Matrix client, DM @slackbot:<your-name>.meldry.com:
```
login-token xoxc-... xoxd-...
```
The bot confirms Successfully logged in as @yourname on My Workspace.

Repeat for additional workspaces — each login-token call adds one workspace.

Option B — OAuth (requires workspace admin to install the Meldry Slack app) #

The workspace admin installs the Meldry Slack app from https://<your-name>.meldry.com/slack/install.
Any user in the workspace can then run login in the bridge bot DM — they're redirected to Slack's OAuth consent screen.
After approval, the bot confirms Logged in via OAuth.

OAuth gives cleaner per-user auth and survives Slack password changes; token auth can break when your Slack session expires.

What gets bridged #

Public channels — each visible as a Matrix room under the workspace space.
Private channels — same, but only to members.
DMs and MPDMs (multi-person DMs) — appear as Matrix DM rooms.
Threads — Slack threads become Matrix threads, replies sync both ways.
Reactions — synced, with emoji translation.
Mentions — @user on Matrix maps to <@UXXX> on Slack and vice versa.
File uploads — images, video, audio, arbitrary files up to Slack's per-workspace limit.
Edits and deletes — bidirectional.

What's not bridged #

Huddles (voice/video) — not supported.
Canvas documents — read-only, rendered as plain text links.
Workflows and apps — appear as bot messages; you can't trigger them from Matrix.
Slack Connect shared channels — the bridge sees messages, but cross-workspace replies can misattribute.

Bridging a specific channel on demand #

By default, after login, all channels you're a member of get bridged. If you don't want that — say, only bridge one or two rooms — pass --no-auto-join in your login command and then run:

join !matrix-room-id #slack-channel-name

Commands reference #

Command	What it does
`login`	OAuth login flow
`login-token xoxc-... xoxd-...`	Personal-token login
`logout`	Unlink the current workspace
`workspaces`	List all linked workspaces
`join <matrix-room> <slack-channel>`	Manually bridge a specific channel
`sync`	Force a full resync
`help`	Full command list

Troubleshooting #

"Invalid tokens" — Your xoxc or xoxd credentials have expired. Log in to Slack in your browser again and copy fresh values.

Missing channels after login — Slack's token-auth only sees channels you're explicitly a member of. Join the channel in Slack first, then run sync.

Emoji not translating — Custom workspace emoji need to be uploaded to Matrix separately. The bridge handles standard emoji automatically.

Slow backfill — Workspaces with thousands of channels take several minutes to import. The sync command is chunked; progress shows in the bridge DM.

"Workspace is paywalled" — Slack free plans limit message history to 90 days. The bridge can only backfill what Slack's API returns.

Limitations #

Workspace-side encryption. Slack does not support end-to-end encryption, so messages in bridged rooms decrypt at the Slack side regardless of Matrix room settings.
Slack rate limits. Slack throttles the Web API aggressively. Large synchronous operations (joining 100 channels at once) will pause and resume.

Unlinking #

To remove a single workspace: logout in the bridge bot DM will prompt you for which workspace. To remove the bridge entirely and free up a bridge slot, disable it from Dashboard → Server → Bridges.