Mattermost vs Rocket.Chat
Mattermost and Rocket.Chat compared for 2026: free editions and their limits, MIT, AGPL and enterprise licensing, PostgreSQL vs MongoDB, hardware sizing, SSO, calls, federation, omnichannel, playbooks, AI, release support windows and paid plans, with a clear pick per situation.
Quick Answer
Mattermost and Rocket.Chat are the two best-known self-hosted Slack alternatives. Both are now open core and sell mostly to regulated, government and defense buyers, with quote-only paid plans. Mattermost runs on PostgreSQL (15+ as of v12.0) and is ChatOps-oriented, with Jira, GitHub and GitLab integrations, Playbooks for incident workflows, self-hosted calls and bring-your-own-LLM agents. Its free options are Team Edition (open source, compiled under MIT, intended for under 250 users, no SSO) and Entry (the Enterprise binary in a free mode with limits such as 10,000 viewable channel messages, best for under 50 users). Rocket.Chat runs on Node.js with MongoDB 8.0 and adds omnichannel customer messaging (WhatsApp, SMS and other channels), Matrix federation and an Apps-Engine for extensions. Its free options are Starter (up to 50 users, with LDAP, SAML and Custom OAuth) and Community (up to 100 concurrent users, core messaging only). Latest releases: Mattermost v12.0.2 (4 November 2026) and Rocket.Chat 9.0.0 (10 November 2026). Pick Mattermost for an engineering or ops team that wants ChatOps on Postgres. Pick Rocket.Chat if you need customer-facing omnichannel, federation with other organisations, or SSO on a free tier.
Last updated November 11, 2026. Covers Mattermost v12.0.2 (4 November 2026) and Rocket.Chat 9.0.0 (10 November 2026), with editions, plans and requirements from mattermost.com, docs.mattermost.com, rocket.chat and docs.rocket.chat, and licences from each repository, read in November 2026.
| Feature | Mattermost | Rocket.Chat |
|---|---|---|
| License | Compiled builds under MIT; source under AGPLv3 or commercial; admin tools and config under Apache 2.0; Enterprise Edition commercial | MIT, except apps/meteor/ee/ and ee/ under Rocket.Chat's enterprise licence |
| Free Editions | Team Edition (open source) and Entry (free mode of Enterprise Edition) | Starter and Community |
| Free-Tier Limits | Team Edition: for under 250 activated users, no SSO. Entry: 10,000 viewable channel messages, no compliance or HA, best for under 50 users | Starter: up to 50 users, premium features with usage limits. Community: up to 100 concurrent users, core messaging, 10,000 push notifications/month |
| Paid Plans | Professional (up to 250 users), Enterprise (unlimited users), Enterprise Advanced (national security) | Commercial, Government, Defense |
| Published Pricing | Not published; all paid plans via sales; per-server licences with quarterly true-forward 6/10 | Not published; 'Get pricing' and custom quotes; non-profit discount programme 7/10 |
| Database | PostgreSQL 15+ (v12.0); MySQL deprecated since v11 | MongoDB 8.0 (replica set of 3 recommended); S3, GCS or MinIO for files |
| Server Stack / Deployment | Single Linux binary or Docker (recommended); Ubuntu 22.04+, Debian Bookworm+, CentOS Stream 9+, RHEL 9+ | Node.js 22/24 (bundled in Docker image and Helm chart); microservices on Kubernetes above 5,000 concurrent users |
| Small-Deployment Sizing | 1–1,000 users: 1 vCPU, 2 GB RAM; 1,000–2,000 users: 2 vCPU, 4 GB RAM | Starter, up to 500 concurrent: Rocket.Chat 2 vCPU/4 GiB/20 GiB + MongoDB 2 vCPU/4 GiB/10 GiB per replica |
| HA & Scale | Professional single server; Enterprise HA cluster to 50,000 concurrent users; Enterprise Advanced 200,000 | Multi-instance HA on premium plans; microservices for more than 5,000 concurrent users |
| SSO & Directory | SAML, OIDC, OAuth, Entra ID, AD/LDAP sync on Professional+; AD/LDAP group sync on Enterprise | LDAP, SAML and Custom OAuth on Starter and premium; built-in OAuth providers on all editions; LDAP/SAML group mapping |
| Voice / Video | Self-hosted group audio calls and screen sharing (Professional+); live transcription on Enterprise | Video via Jitsi/BigBlueButton (Community) or also Pexip, Google Meet, Zoom (Starter); WebRTC calls; VoIP add-on via FreeSWITCH |
| Federation / External Collaboration | Connected workspaces across Mattermost instances; federated channels with Teams and Matrix interop (Enterprise) | Federation between Rocket.Chat servers; Matrix federation (Government, Defense); XMPP bridge (Defense) |
| Customer Omnichannel | No | Yes: WhatsApp, SMS and other channels |
| Workflows & Integrations | Playbooks; Jira, GitHub, GitLab, Zoom integrations; bots, webhooks, APIs, drivers, third-party extensions | Incoming/outgoing webhooks (isolated-vm scripts), Apps-Engine apps, REST API, embeddable front-end |
| AI Features | Agents with bring-your-own multi-LLM (Professional+); MCP and agent controls on Enterprise | Rocket.Chat AI (sovereign AI) as an add-on; MCP support |
| Compliance & Retention | Data retention, legal hold, compliance export on Enterprise; FIPS 140-3 and STIG-hardened images | Retention policies, tamper-evident audit logs, message export, E2EE on premium plans; FIPS 140-3 add-on (Government, Defense) |
| Clients | Web, Windows, macOS, Linux, iOS, Android | Web, desktop, iOS, Android |
| Vendor-Hosted Option | Mattermost Cloud Enterprise (single-tenant, via sales) | Rocket.Chat-managed dedicated hosting (premium plans) |
| Release & Support Policy | Monthly on the 16th; each release supported about 3 months; Extended Support Releases (e.g. v11.7 ESR) | Standard releases supported 6 months, LTS 12 months (8.9 LTS until 31 Oct 2027) |
| Latest Release (Nov 2026) | v12.0.2 (4 Nov 2026); v12.1 in release candidates | 9.0.0 (10 Nov 2026); 8.9.1 LTS |
Mattermost
Open-core, self-hosted collaboration platform for technical and operational teams: channels, threads, file sharing, Playbooks, calls and AI agents, with deep DevSecOps integrations. Distributed as an MIT-licensed compiled Team Edition and a commercial Enterprise Edition that runs free as Entry or unlocks Professional, Enterprise and Enterprise Advanced with a licence.
Pros
- PostgreSQL-based with a published minimum-version policy, so it fits shops that already run and back up Postgres
- ChatOps focus: pre-packaged Jira, GitHub, GitLab and Zoom integrations, plus bots, webhooks, APIs and third-party extensions
- Light footprint: 1 vCPU and 2 GB RAM is the stated sizing for 1 to 1,000 users on a single server
- Playbooks for repeatable incident and operations workflows, with automated triggers on Enterprise
- Bring-your-own-LLM agents that keep data on your network, from Professional upward
- Predictable monthly releases on the 16th, plus Extended Support Releases for slower upgrade cycles
Cons
- No public price list: Professional, Enterprise and Enterprise Advanced are all 'Contact Sales'
- Team Edition is losing SSO and is not recommended for sensitive workloads, so free SSO now means running the Entry mode of the commercial binary
- Entry's free mode limits viewable history to 10,000 channel messages and leaves out compliance features and high availability
- No customer-facing omnichannel or live-chat product; Mattermost is built for internal teams
Best For
Engineering, DevOps, SRE and security teams that want self-hosted ChatOps on PostgreSQL, with Jira, GitHub and GitLab workflows, incident Playbooks and optional local LLM agents.
Rocket.Chat
Open-core communications platform on Node.js and MongoDB with team chat, voice and video, federation and an omnichannel module for customer conversations. Licensed MIT outside its ee/ directories, offered free as Starter or Community and commercially as Commercial, Government and Defense plans.
Pros
- Free Starter tier includes LDAP, SAML and Custom OAuth for up to 50 users, with unlimited push notifications
- Omnichannel module brings customer and citizen conversations (WhatsApp, SMS and more) into the same workspace
- Matrix federation, plus an XMPP bridge on Defense, for shared rooms with other organisations without shared infrastructure
- Most of the codebase is MIT-licensed, a permissive licence with no copyleft obligations for forks
- Flexible video options: Jitsi and BigBlueButton on Community; Pexip, Google Meet and Zoom on Starter; FreeSWITCH-based VoIP as an add-on
- Clear support windows: standard releases supported 6 months and LTS releases 12 months
Cons
- MongoDB is required (8.0 for Rocket.Chat 8.x and 9.0), with a 3-member replica set recommended, which is extra operational work if you run Postgres elsewhere
- Heavier baseline: the Starter reference sizing is 2 vCPU and 4 GiB for Rocket.Chat plus 2 vCPU and 4 GiB for each MongoDB node
- Community edition is core messaging only, and 9.0 made Custom OAuth a premium feature
- No public price list for Commercial, Government or Defense; several advertised defense features are marked as planned for 2026
Best For
Organisations that need customer-facing omnichannel next to internal chat, public-sector and partner networks that federate over Matrix, and small teams that want free SAML or LDAP sign-in.
Free editions: what you actually get without paying
Both vendors have reshaped their free tiers, and the details decide most small-team choices. Mattermost has two. Team Edition is the open-source build, compiled under MIT and deployed as a single Linux binary with PostgreSQL. It is intended for teams under 250 activated users that don't need SSO, and Mattermost says SSO is being removed from it as the GitLab Omnibus bundle is redefined. Entry is the commercial Enterprise Edition binary running without a licence. It includes Enterprise Advanced features but caps viewable history at 10,000 channel messages across the server, leaves out compliance features and high availability, and will limit Playbook runs and push notifications in a future release. Mattermost recommends it for teams under 50 users. Rocket.Chat also has two. Starter allows up to 50 users and includes many premium capabilities with usage limits, including LDAP, SAML and Custom OAuth, unlimited push and more video integrations. Community is capped at 100 concurrent users, covers core messaging only and sends up to 10,000 push notifications a month. Rocket.Chat 9.0 also moved Custom OAuth behind the premium licence, although built-in providers such as GitHub and Google still work.
Licensing in plain terms
Mattermost's LICENSE file has three layers. Compiled builds produced by Mattermost, Inc. are licensed to you under MIT. If you compile the source yourself, you use it under AGPLv3 or a commercial licence, and admin tools and configuration files are Apache 2.0. Community builds must also replace the Mattermost trademark. Enterprise Edition is a separate commercial licence that forbids tampering with the licence-key mechanism. In practice, running the official binaries is unrestricted, while forking and redistributing a modified server brings AGPL obligations. Rocket.Chat's LICENSE is simpler. Everything outside the apps/meteor/ee/ and ee/ directories is MIT, and the ee/ code sits under Rocket.Chat's enterprise licence, which is what Starter and the paid plans unlock. If you plan to build a product on top of the server code, Rocket.Chat's permissive core is easier to work with. On paid licensing, Mattermost requires a licence per server, counts a high-availability cluster as one server, and bills extra seats quarterly on a true-forward basis. Rocket.Chat prices Commercial, Government and Defense by quote, with add-ons for AI, VoIP, FIPS and Mission Critical support.
Running it: PostgreSQL vs MongoDB and the hardware bill
Mattermost needs PostgreSQL. As of v12.0 (October 2026) the minimum is PostgreSQL 15, and MySQL has been deprecated since v11. Its minimum-version policy follows the PostgreSQL community's end-of-life dates, with nine months' notice. The official sizing is small: 1 vCPU and 2 GB RAM for 1 to 1,000 users and 2 vCPU and 4 GB for up to 2,000, with Docker recommended on Ubuntu 22.04+, Debian Bookworm+ or RHEL 9+. RHEL 7 and 8 were dropped in v12.0. Rocket.Chat needs MongoDB, version 8.0 for the 8.x line and for 9.0, and Node.js 22 or 24, which is bundled in the official Docker image and Helm chart. Its Starter reference deployment, for up to 500 concurrent users, is 2 vCPU, 4 GiB and 20 GiB for Rocket.Chat plus 2 vCPU, 4 GiB and 10 GiB for each of three recommended MongoDB replica-set members. Above 5,000 concurrent users it moves to microservices on Kubernetes. Rocket.Chat also recommends S3, GCS or MinIO for uploads instead of GridFS. If your team already backs up and monitors Postgres, Mattermost adds less to the ops load.
Where each one goes beyond chat
The products differ in direction once you go beyond channels and threads. Mattermost leans into technical operations. It offers Playbooks for incident response with tasks, automated triggers and retrospectives, self-hosted group calls and screen sharing (with live transcription and AI summaries on Enterprise), and integrations with Jira, GitHub and GitLab. From Professional upward, AI agents use the LLMs you bring, and Enterprise adds agent management, MCP and per-user token tracking. Mattermost also sells an out-of-band channel for when primary communications fail. Rocket.Chat leans into communication with people outside the team. Omnichannel connects WhatsApp, SMS and other channels to agents in the same workspace. Federation creates shared rooms across independent Rocket.Chat servers, with Matrix federation on Government and Defense and an XMPP bridge on Defense. The front-end can also be embedded in other apps. Both have SSO, retention, audit and export features on paid plans, and both now market FIPS 140-3 builds. Rocket.Chat's pricing page marks several defense features, such as STIG hardening and post-quantum E2EE, as planned for 2026.
Upgrades, support windows and release cadence
Mattermost ships a server release on the 16th of every month. Each release has a short support window: v12.0 shipped on 16 October 2026 and is supported until 15 January 2027. Extended Support Releases such as v11.7 cover slower upgrade cycles, and the v10.11 ESR reached end of life on 15 August 2026. Mattermost fully tests upgrades from one ESR to the next, while skipping an ESR is supported but untested. Security patches land across several lines at once. On 5 November 2026, for example, Mattermost published v11.11.4, v11.10.5, v11.7.15 and v10.11.26, a day after v12.0.2. Rocket.Chat supports standard releases for 6 months and LTS releases for 12 months. 8.9 LTS is supported until 31 October 2027 and 8.5 LTS until 30 June 2027. Rocket.Chat 9.0.0 arrived on 10 November 2026 with breaking changes: webhook scripts now run untranspiled in isolated-vm, the legacy /ufs file endpoint is gone, and Custom OAuth requires a premium licence. Moving from Rocket.Chat 7.x to 8.x also required upgrading MongoDB to 8.0 first. Rocket.Chat also warns that its official desktop and mobile apps may refuse to connect to a server that has reached end of life.
Verdict
Pick Mattermost for an internal engineering, DevOps or security team. It runs on PostgreSQL, sizes small (1 vCPU and 2 GB RAM for up to 1,000 users), and is built around ChatOps: Jira, GitHub and GitLab integrations, Playbooks for incidents, self-hosted calls, and agents that use your own LLM. For a small team, start with Entry if you want SSO and Playbooks in a free mode and can live with 10,000 messages of viewable history, or with Team Edition if you want a plain MIT-licensed chat server for under 250 users without SSO. Pick Rocket.Chat when chat has to reach outside your team. That means customer or citizen conversations through omnichannel, federation with partner organisations over Matrix, or an MIT-licensed core you plan to extend. Its free Starter plan is also the cheaper route to SAML or LDAP sign-in for up to 50 users. Accept that it needs MongoDB 8.0 run as a replica set. If you are already in a procurement process, both vendors price by quote and both target regulated and defense buyers, so compare actual quotes and support SLAs rather than list features.