Mattermost vs Rocket.Chat

Mattermost

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.

Rocket.Chat

The homepage sells messaging bundled with voice, video, screen sharing and apps, but not one word about channels, threads, mentions or search — I cannot confirm my team can find last spring's decision at all. Threads and readable history are the whole game on a busy Tuesday, and this sheet is silent on both.

Mattermost

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.

Rocket.Chat

"Fully encrypted conversations" and "advanced access and identity controls" are assertions without mechanism: no word on who holds keys, end-to-end mode, device verification, session revocation or how guests are scoped. Self-hosting at least puts the server under my roof, which keeps this off the floor.

Mattermost

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.

Rocket.Chat

"Granular data retention policies" and "comprehensive audit logs" are named outright, which clears the low bar. But export format, legal hold, eDiscovery and whether any analytics can be switched off organisation-wide are entirely absent — a works council gets half an answer.

Mattermost

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.

Rocket.Chat

Open source on GitHub, on-prem / private cloud / isolated VPC / fully air-gapped options, air-gapped across 40+ classified programs, and "full control over where and how your data is stored" — custody genuinely sits with the customer. What's missing is a documented complete export with files and metadata and a migration path the vendor spells out; "No vendor lock-in" is a slogan, not a procedure.

Mattermost

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.

Rocket.Chat

A marketplace with pre-built and custom apps, plus developer guides, is a real framework story — better than a webhook stub. But there is no documented REST API, webhooks, slash commands, SCIM, rate limits or sandbox anywhere in the evidence, so I'd be committing my team to an ecosystem I can't audit or build against predictably.

Mattermost

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.

Rocket.Chat

The sovereignty pipeline has nothing on record: the contracting entity is a US Delaware corporation, hosting is unstated, subprocessors are unnamed, no certification published. The only European story is a customer testimonial about hosting it themselves on AWS — self-hosting can rescue custody, but the vendor's own chain is opaque, and a marketing line about a "sovereign cloud" option is not a subprocessor list.

Mattermost

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.

Rocket.Chat

Three captures of the pricing page produced plan names, FAQs about pilots and non-profit rates, and a "planned for release in 2026" footnote — not a single per-user figure, billing term, storage limit or VAT note. I cannot compute an annual invoice for forty people from this, so every real tier is a sales conversation.