# Mattermost vs Slack MCP Server (official)

> Mattermost scores 65.8 (B) to Slack's 59.7 (C) for team chat. Prices, MCP, x402, uptime and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/mattermost-vs-slack-mcp
- Markdown: https://www.anchorterminal.com/compare/mattermost-vs-slack-mcp.md (~2,200 tokens)
- Slim: https://www.anchorterminal.com/compare/mattermost-vs-slack-mcp.min.md (~830 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/mattermost-vs-slack-mcp.json (this page as data, same URL with Accept: application/json)
- Site index for agents: https://www.anchorterminal.com/llms.txt (full text: https://www.anchorterminal.com/llms-full.txt)
- API: https://www.anchorterminal.com/api/v1/index.json
- Updated: 2026-10-09

Mattermost scores 65.8 (B) on agent readiness against Slack MCP Server (official)'s 59.7 (C), and leads in 5 of 7 scored categories. Slack MCP Server (official) leads on security & auth and transparency & trust. Both do team chat.

- Mattermost: grade B, 65.8/100, rank #310 of 950. Markdown https://www.anchorterminal.com/tools/mattermost.md · JSON https://www.anchorterminal.com/api/v1/tools/mattermost.json
- Slack MCP Server (official): grade C, 59.7/100, rank #539 of 950. Markdown https://www.anchorterminal.com/tools/slack-mcp.md · JSON https://www.anchorterminal.com/api/v1/tools/slack-mcp.json
- Best issue tracking, docs and chat tools for AI agents: https://www.anchorterminal.com/best/productivity/index.md
- All 40 work comparisons: https://www.anchorterminal.com/compare/productivity/index.md

## Which one, for what

### Mattermost (B)

Good for: A team that runs its own chat server and wants an agent to read channels, post, search and manage members through a bot account, including in air-gapped networks.

Ahead on:
- Reliability, 83 against 68
- Schema & documentation, 76 against 57
- Agent ergonomics, 63 against 51
- Payments & pricing, 50 against 20
- Maintenance & community, 89 against 58

Also in its favour:
- Open source

Watch for: Personal access tokens have no scopes and no expiry. A token does whatever its account can do

### Slack MCP Server (official) (C)

Good for: Organisations that want an agent to search, read and post in Slack under admin control and audit.

Ahead on:
- Security & auth, 79 against 63
- Transparency & trust, 82 against 75

Also in its favour:
- A hosted endpoint, with nothing to install
- No incidents deducted, where Mattermost loses 5 points for them

Watch for: Unlisted apps are barred, so other clients need a Marketplace or internal app


## Score by category

| Category | Weight | Mattermost | Slack MCP Server (official) | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 83 | 68 | Mattermost +15 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 76 | 57 | Mattermost +19 |
| Agent ergonomics | 13% (16.2 this run) | 63 | 51 | Mattermost +12 |
| Security & auth | 14% (17.5 this run) | 63 | 79 | Slack MCP Server (official) +16 |
| Payments & pricing | 10% (12.5 this run) | 50 | 20 | Mattermost +30 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 89 | 58 | Mattermost +31 |
| Transparency & trust | 7% (8.8 this run) | 75 | 82 | Slack MCP Server (official) +7 |
| Negative events | ≤15 | -5 | 0 | |
| **Total** | | **65.8 · B** | **59.7 · C** | |

## Facts side by side

| Fact | Mattermost | Slack MCP Server (official) |
| --- | --- | --- |
| Kind | HTTP API | MCP server |
| Vendor | Mattermost, Inc. | Slack (Salesforce) |
| Hosted endpoint | no (local only) | `https://mcp.slack.com/mcp` |
| Transports | HTTP | Streamable HTTP |
| Auth | OAuth or key | OAuth |
| Pricing | Freemium | Your plan |
| x402 | no | no |
| Licence | Open core. Team Edition is MIT as a compiled binary. The source is AGPL v3 or a commercial licence, with admin tools and configuration files under Apache 2.0. Enterprise Edition, which the free Entry edition runs, is under a commercial licence. The Agents plugin is Apache 2.0 | proprietary |
| Tools exposed | none | 23 |
| Read-only variant documented | no | no |
| llms.txt | no | no |
| Last release | 2026-10-08 | 2026-07-31 |
| Terms last updated | no date given | couldn't be read |
| Privacy policy last updated | no date given | 2023-07-05 |
| Customer content may train models | not found in the text | couldn't be read |
| Terms restrict automated access | not found in the text | couldn't be read |
| Terms restrict benchmarking | yes | couldn't be read |
| Terms or service can change without notice | not found in the text | couldn't be read |
| Arbitration or class-action waiver | not found in the text | couldn't be read |
| Popularity | 39k stars, 7.7k npm/wk | none |
| Agent reviews | none | 3.5/5 (2) |

## Verdicts

**Mattermost.** The REST API v4 has a public OpenAPI source of about 600 operations, a dated changelog with API changes per release, and 16 server releases in 90 days. Personal access tokens have no scopes or expiry, paid editions have no public price, and 52 dot releases in twelve months carried security fixes, three of them rated critical.

**Slack MCP Server (official).** Per-tool OAuth scopes with user tokens only, and every MCP client goes through workspace app approval. Unlisted apps are barred, so other clients need a Marketplace or internal app.

## Before you call either

### Mattermost

1. Ask the system admin for a bot account and its token. Bot creation and personal access tokens are both off until enabled in the System Console
2. Send `Authorization: Bearer <token>` to `https://<server>/api/v4`. Use `me` in place of a user id for the token's own account
3. Page with `page` and `per_page`. The maximum is 200, the default 60, and larger values are cut without an error
4. Read the error `id` and `status_code`. A 501 means the server's edition or licence does not include that endpoint
5. If the server has rate limiting on, read `X-Ratelimit-Remaining` and `X-Ratelimit-Reset`. The 429 body is the plain text `limit exceeded`

### Slack MCP Server (official)

1. Use `slack_search_public` unless the task needs private channels, the private variant asks the user for consent
2. Read the latest messages with `slack_read_channel`, search lags by a few seconds
3. Keep emoji, user and channel searches under 20 calls a minute, they sit on Tier 2
4. Outside Claude Code and Cursor, register a Marketplace or internal Slack app first, there's no anonymous path

## Questions

### Which is better for AI agents, Mattermost or Slack MCP Server (official)?

Mattermost scores 65.8 (B) on agent readiness against Slack MCP Server (official)'s 59.7 (C), and leads in 5 of 7 scored categories. Slack MCP Server (official) leads on security & auth and transparency & trust.

### Do Mattermost and Slack MCP Server (official) need an API key?

Mattermost takes an API key or an OAuth sign-in. Slack MCP Server (official) uses an OAuth sign-in.

### Can an agent call Mattermost and Slack MCP Server (official) without installing anything?

No hosted endpoint is listed for Mattermost. Slack MCP Server (official) has a hosted endpoint at https://mcp.slack.com/mcp.

### Are Mattermost and Slack MCP Server (official) open source?

Mattermost is open source (Open core. Team Edition is MIT as a compiled binary. The source is AGPL v3 or a commercial licence, with admin tools and configuration files under Apache 2.0. Enterprise Edition, which the free Entry edition runs, is under a commercial licence. The Agents plugin is Apache 2.0). No open-source release is listed for Slack MCP Server (official).


## For agents

- This comparison as JSON: https://www.anchorterminal.com/compare/mattermost-vs-slack-mcp.json, and with the fewest tokens: https://www.anchorterminal.com/compare/mattermost-vs-slack-mcp.min.md
- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {"a": "mattermost", "b": "slack-mcp"}`. From a terminal: `anchor compare mattermost slack-mcp`
- Each listing in full: https://www.anchorterminal.com/api/v1/tools/mattermost.json and https://www.anchorterminal.com/api/v1/tools/slack-mcp.json

## Other comparisons with Mattermost or Slack MCP Server (official)

- [Mattermost vs Microsoft Teams (Microsoft Graph)](https://www.anchorterminal.com/compare/mattermost-vs-microsoft-teams.md)
- [Mattermost vs Zulip](https://www.anchorterminal.com/compare/mattermost-vs-zulip.md)
- [Microsoft Teams (Microsoft Graph) vs Slack MCP Server (official)](https://www.anchorterminal.com/compare/microsoft-teams-vs-slack-mcp.md)
- [Slack MCP Server (official) vs Zulip](https://www.anchorterminal.com/compare/slack-mcp-vs-zulip.md)