Mattermost

YES

Replaceable in one session with an AI coding agent.

Open-source team chat you run yourself: channels, threads, calls and integrations, with the messages staying on your own infrastructure.

Promptfree, for everyone, and the only version there is

Self-host it, and plan for the push relay.

RUNNING IT
- Docker Compose with Postgres, behind a reverse proxy with TLS
- Object storage for file uploads; local disk becomes a migration problem later

THE PART PEOPLE MISS
- Mobile push goes through a relay because Apple and Google require signed certificates tied to the published app
- The hosted push service is free for small deployments; running your own means building and publishing your own apps
- Decide this before you migrate, not after

BACKUPS
- Postgres and the file store, nightly, off the machine, restored once

RETENTION
- Decide how long messages are kept and enforce it. An unbounded chat archive is a liability as well as a disk cost

Include the compose file, the push decision and the retention policy.

What you lose

Compliance export, retention policies and single sign-on on the paid tier
Support when a message store needs recovering
Mobile push, which needs a relay you would otherwise operate

If you would rather not build

Rocket.Chat, similar and open

The escape hatch

open source · no votes, no paid placement

Mattermost

The product itself, free to self-host with the team edition.

mattermost/mattermostfree · open source

Zulip

Open team chat organised by topic, which scales better in writing.

zulip/zulipfree · open source

Why this verdict

our own opinion · changed only by a person

78/100

Verdict yes at 78. Self-hosting is well trodden; mobile push is the one thing that is not obvious until you hit it.

History

tracked since 10 Aug 2026 · nothing is ever overwritten

Interest · last 30 days

Nothing recorded yet. This chart fills in once the page has visitors, votes or prompt copies — it will not draw a flat line to look busy.

Questions about Mattermost

answered from the record above

Is Mattermost free?

No — the plan we track is $10 a month. Professional at around $10 per user per month billed monthly; the team edition is free to self-host.

Can you replace Mattermost by building your own?

YES. Replaceable in one session with an AI coding agent. Replacement score 78 out of 100, build time one session. Read what you lose before you decide.

How much does Mattermost cost?

$10 a month on Professional — $120 a year. Recorded 10 Aug 2026.

What do you lose by replacing Mattermost?

Compliance export, retention policies and single sign-on on the paid tier; Support when a message store needs recovering; Mobile push, which needs a relay you would otherwise operate. If any of those carry weight for you, keep paying.

Is there an open-source alternative to Mattermost?

Yes: Mattermost, Zulip. The prompt on this page is for when you want it your way instead.

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