Verified comparison

Slack is an alternative
to Mattermost

$0/mo (Free) vs Mattermost at — — covering 89% of the 9 compared capabilities.

Same job. Way less money.

Comparison scenario

Every cheaper-than claim is tied to a defined scenario — never a bare list price.

Scenario

10 seats, monthly billing · USD · prices as observed on official pricing pages.

Mattermost basis

plan at —, the cheapest paid plan.

Slack basis

Free: 0 USD/monthly.

The short version

We list 1 assessed alternative; Mattermost's own price is not verified yet, so no cheaper-than claim is made.

Slack covers 89% of the 9 capabilities compared against Mattermost. ✓ native · ◐ via integration · ✗ not found.

Capability	Slack	Mattermost
Channels & group messaging	✓	✓
Threaded conversations	✓	✓
Guest & external collaboration	✓	✓
SAML single sign-on	✓	✓
Self-hosted deployment	✗	✓
Compliance exports & audit logs	✓	✓
AI search & summaries	✓	✓
App integrations	✓	✓
Workflow automation	✓	✓

Capabilities Mattermost has that Slack lacks.

Self-hosted deployment — Run the chat platform on your own infrastructure.
Missing from Slack.

The same comparison recomputed at three sizes. Plan caps change who is cheapest.

Advertised prices in USD as observed on the official pricing pages — per-seat and transaction-fee plans are marked.

Slack

Mattermost

What does Slack lack compared with Mattermost?

Self-hosted deployment — 1 of the 9 compared capabilities.

When were these prices checked?

Mattermost: 2026-09-07; Slack: 2026-08-26 — on the official pricing pages.

https://mattermost.com/pricing/ (official_pricing, checked 2026-09-07)
https://mattermost.com/pricing/#skip-nav-target (official_pricing, checked 2026-09-07)
Slack data last verified 2026-08-26