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Mattermost

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Panel rating · 6 judges · How to read the stars

Category median

Sovereignty: 1 of 4 dimensions proven

0–5 in half steps. 5 means the rubric's top anchor is met on the evidence.

by Mattermost, Inc. · mattermost.com

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Read this page as one judge. Each weighs the same scores by what they care about.

The Team Lead

Weighted verdict

Runs a distributed team and needs the tool people actually open. Wants threads that stay readable, search that finds last spring's decision, and channels that can be tidied without losing history. Unmoved by feature lists that do not survive a busy Tuesday.

Same scores as the panel view — this lens weights them the way this judge cares.

Scored by The Team Lead

Channels, threads & search

How this is scored

The daily surface: channel model, threading, mentions, files, and whether search can find a decision made eighteen months ago.

0 — Flat group chats with no threads; search covers recent messages only, and history is capped.

3 — Channels and direct messages with basic search, but threading is awkward or absent and file handling is a plain attachment list.

5 — Public and private channels, real threads, mentions and reactions, file sharing with previews, and full-text search across the whole history.

8 — Cross-organisation or guest channels with clear boundaries, message editing history, pinned and saved items, search with filters by channel, person and date, and a documented history limit or none at all.

10 — The archive is a working knowledge base: search that ranks well across years, threads that stay readable, channel lifecycle management (archive, rename, merge) without losing history, and export of a conversation in a form a human can read.

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The Team Lead

Channels, real threaded discussions and link and file previews are on the plan page, and the API docs show threads you can pull and move between channels — the move is marked beta, but it's the tidying-without-losing-history capability I ask for. Search is described as core search up to three million posts on Professional and enterprise search above that. I found no public information on end-user search filters by person or date, pinned or saved items, or how guest-channel boundaries are drawn, which keeps it off the upper band. 2 5 6 13

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Encryption & access control

How this is scored

What is encrypted and against whom, plus who can reach which room. Judged on documented mechanism, since "encrypted" in this category usually means the vendor holds the keys.

0 — Transport encryption only, undocumented; no role model beyond admin, guests indistinguishable from members.

3 — TLS and encryption at rest with vendor-held keys, basic roles, and guest access that mostly works.

5 — The above plus configurable roles per channel, SSO, guest accounts with scoped visibility, and a clear statement of what the vendor can read.

8 — Optional end-to-end encryption for direct messages or private rooms with the trade-offs named, device verification, session management an admin can revoke, and documented key handling.

10 — End-to-end encryption as a first-class mode — documented or open cryptography, cross-device key management that ordinary users survive, identity verification, and the vendor stating plainly what it cannot decrypt.

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The Team Lead

Transport and at-rest encryption are documented down to the mechanics — TLS with named ciphers, disk-level encryption via LUKS, BitLocker or TDE, S3-managed keys — and access control runs from granular role-based permissions and AD/LDAP sync up to attribute-based zero-trust channel access. The deployment guide states plainly that it does not encrypt within the database so that search and compliance reporting keep working, which is the honest statement I want from a vendor. We found no public information on end-to-end encryption, device verification or admin-revocable sessions, so it sits mid-band. 2 7 8

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Retention, discovery & co-determination

How this is scored

The archive as a legal object: retention policies, export for discovery, audit, and the monitoring features a works council will ask to have switched off.

0 — No retention policy, no export beyond a manual copy, no audit log, and presence or activity analytics that cannot be disabled.

3 — Manual export of some data and a global history limit, but no per-channel retention, no audit log and no admin control over analytics.

5 — Configurable retention per channel or workspace, admin export in a documented format, an audit log of administrative actions, and status or presence that a user can control.

8 — Legal-hold and eDiscovery export including edits and deletions, retention executed per policy and evidenced, full admin audit trail, and activity analytics switchable off organisation-wide.

10 — Built to pass a works agreement and a subpoena on the same day: granular retention with documented deletion, discovery export a lawyer can use, complete audit, and no individual-level productivity scoring anywhere in the product.

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The Team Lead

The compliance export machinery is genuinely deep — CSV, Actiance XML, Global Relay EML and Proofpoint formats, daily scheduled jobs, filters by date, user and keyword, and messages tracked by identifier as they are edited or deleted across export batches — with legal hold and eDiscovery automation named on the Enterprise plans. Default retention keeps all messages including edits and deletes, with customisable retention depending on plan. Playbooks and Boards are excluded from compliance export, and we found no public information on a full administrative audit trail or an organisation-wide switch for activity analytics. 2 4 9 10

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Deployment & data custody

How this is scored

Whether the customer can hold their own archive: self-hosting, private cloud, open source, federation, and what an exit actually looks like.

0 — Cloud-only, proprietary, with export limited to a partial archive.

3 — Cloud-only, but with a documented full export in an open-ish format.

5 — A private-cloud or dedicated-instance option, or a self-hosted edition that lags the cloud significantly; full export documented.

8 — A genuine self-hosted edition close to feature parity, or open-source core with a documented upgrade path, plus complete export including files and metadata.

10 — Custody is the customer's: open-source or source-available server, self-hosting supported as a first-class deployment, open protocol or federation, and a migration path in and out that the vendor documents rather than resists.

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The Team Lead

This is where they are strongest: the same server installs via Kubernetes, Linux or containers, a documented air-gap runbook with registry mirroring covers every edition down to Team Edition, and FIPS-compliant, STIG-hardened images are published. The privacy policy says the self-hosting customer controls the processing of end-user data, telemetry is opt-out, and Matrix-protocol federation is named on the Enterprise plan. I held back from the top only because the captured pages show compliance-format exports rather than a documented full workspace export and import for migration. 2 3 4 11 12

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Integrations & extensibility

How this is scored

Bots, webhooks, app framework, identity — whether the chat becomes the place work is noticed, and whether that is buildable without a partner agreement.

0 — No API, no webhooks, no bots.

3 — Incoming webhooks and a handful of native integrations; no bot framework, no documented limits.

5 — Documented REST API, incoming and outgoing webhooks, slash commands, a bot account model, and SSO.

8 — A proper app framework with interactive components, event subscriptions with retries, SCIM provisioning, documented rate limits and a sandbox.

10 — A platform: versioned API with a deprecation policy, an app directory or plugin system with permissions a customer can audit, and integrations the vendor maintains rather than lists.

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The Team Lead

There's a documented REST API with bearer auth and per-endpoint permissions, incoming and outgoing webhooks on every plan including the free Entry level, Slack webhook format compatibility for migration, interactive dialogs and Blocks for structured posts, and administrators can enforce webhook channel locking. GitLab notifications land through the standard webhook path, which is the busy-Tuesday test. We found no public information on slash commands, SCIM provisioning, documented rate limits or a sandbox, so it stops short of a full platform story. 2 6 13 14

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European sovereignty

How this is scored

Where the archive and its metadata live, who the contracting entity is, which subprocessors touch it. Independently sourced by the sovereignty pipeline; scored here as this buyer weighs it.

0 — Non-EU vendor and contracting entity, hosting unstated or non-EU, subprocessors unnamed.

3 — EU data residency offered for message content while metadata, search indexes or support tooling remain non-EU, or the contracting entity sits outside the EU.

5 — EU hosting as standard and an EU contracting entity, but parts of the chain — notifications, AI features, analytics — are non-EU without an explained safeguard.

8 — EU hosting on named infrastructure, EU contracting entity, full subprocessor list published, any non-EU processing named with its legal basis.

10 — Sovereign end to end and evidenced: vendor, entity, hosting and every subprocessor European, certification published, and a self-hosted option that removes the question.

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The Team Lead

The contracting entity is Mattermost, Inc. in California, transfers to the United States are disclosed in the privacy policy, and the captured pages give no official subprocessor list for the vendor-managed cloud — Azure and AWS appear only as customer-chosen hosting. What rescues a European deployment is custody: self-hosting with a telemetry opt-out and customer control of end-user data, plus fully documented air-gap operation. We found no public information on EU data residency being offered, so this stays near the bottom for anyone buying the vendor's cloud. 3 4 12

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Pricing transparency not rated — the vendor publishes no price

How this is scored

Whether a buyer can compute the annual invoice for their headcount — including the retention, compliance and guest features they actually need — from public pages alone.

0 — No public prices at all; every tier is a sales conversation.

3 — A per-user headline exists, but the tier where retention control, SSO or compliance export begins is unstated.

5 — Per-user prices public with billing period stated, but at least one commonly needed capability (unlimited history, SSO, eDiscovery) sits in an unpriced enterprise tier.

8 — Every tier priced publicly with per-user maths, history and storage limits, feature boundaries, minimum term and VAT treatment stated; self-hosted licensing priced too where offered.

10 — Complete price computability: annual invoice derivable for a given headcount and deployment choice, including guest users, storage and any per-instance licence.

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The Team Lead

Every named plan — Professional, Enterprise, Enterprise Advanced — routes through "Contact Sales", "Get Pricing" or "Request Quote", and no per-user figure appears anywhere in the captured pages. A free limited-use Enterprise Advanced edition exists for evaluation and FAQs cover how licences are sold and seat overage, but the compliance and eDiscovery capabilities a buyer needs sit in the sales-conversation tiers. I cannot compute an annual invoice for my headcount from anything published here. 2 10 11

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European sovereignty — proven facts

1 of 4 dimensions proven

Built only from facts shown on the vendor's own pages. A dimension we could not prove is left open, not scored as zero.

Ownership Not determined — uncited Report an error
Data residency Not determined — uncited Report an error
Subprocessors US CLOUD Act reach ⚠ unverified 0/2 pts 3 Report an error

Where this could be wrong

What we left out

A claim that does not survive our checks costs us the claim, not the page. This is what was taken off this one.

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Sources (14)

The pages every claim on this page was read from — each one checked, dated, and kept verifiable.

  1. 1 Vendor homepage mattermost.com Checked 15 Sep 2026 Details →
  2. 2 Pricing mattermost.com Checked 15 Sep 2026 Details →
  3. 3 Security page mattermost.com Checked 15 Sep 2026 Details →
  4. 4 Privacy policy mattermost.com Checked 15 Sep 2026 Details →
  5. 5 Channels, threads & search — found from sitemap docs.mattermost.com Checked 1 Oct 2026 Details →
  6. 6 Channels, threads & search — found from sitemap docs.mattermost.com Checked 1 Oct 2026 Details →
  7. 7 Encryption & access control — found from sitemap docs.mattermost.com Checked 1 Oct 2026 Details →
  8. 8 Encryption & access control — found from sitemap docs.mattermost.com Checked 1 Oct 2026 Details →
  9. 9 Retention, discovery & co-determination — found from sitemap docs.mattermost.com Checked 1 Oct 2026 Details →
  10. 10 Retention, discovery & co-determination — found from sitemap docs.mattermost.com Checked 1 Oct 2026 Details →
  11. 11 Deployment & data custody — found from sitemap docs.mattermost.com Checked 1 Oct 2026 Details →
  12. 12 Deployment & data custody — found from sitemap docs.mattermost.com Checked 1 Oct 2026 Details →
  13. 13 Integrations & extensibility — found from sitemap docs.mattermost.com Checked 1 Oct 2026 Details →
  14. 14 Integrations & extensibility — found from sitemap docs.mattermost.com Checked 1 Oct 2026 Details →