Rocket.Chat vs Mattermost (2026): Free Limits, Self-Hosting & Costs

Quick Verdict: Two Free Tiers Each, and No Public Paid Prices

Choose Rocket.Chat Starter if a self-hosted team of up to 50 added users wants LDAP or SAML sign-on, read receipts, retention rules and unlimited push notifications without a subscription. Choose Mattermost Entry if a team of fewer than 50 people wants the Enterprise Edition feature set—Playbooks, Boards, Calls and AI agents—and can live with documented history and usage limits. Pick the open-source editions, Rocket.Chat Community or Mattermost Team Edition, only when you have read exactly which capabilities they omit.

The decisive change in 2026 is that neither vendor publishes a per-seat paid price anymore. Rocket.Chat's pricing page lists Commercial, Government and Defense plans behind a sales contact, and its Pro plan became legacy on April 29, 2026. Mattermost's pricing page lists Professional, Enterprise and Enterprise Advanced without dollar amounts and sells prepaid annual seats. For most small teams, the real comparison is therefore between the free tiers and your own hosting bill, not between two published subscription prices.

Research method: official pricing, plan, licensing and documentation pages checked October 21, 2026. This is a documentary comparison, not a hands-on deployment, load, security or migration test. Budget figures use explicitly labeled planning assumptions, excluding taxes, labor rates and vendor quotes you must obtain yourself. The Rocket.Chat review, Mattermost review and team communication category provide context; the dated primary sources below govern this comparison's current claims.

The Four Free Options: Starter, Community, Entry and Team Edition

Rocket.Chat's plans documentation describes two free entry points. Every workspace deployed on Rocket.Chat 6.5 or later is provisioned as a Starter workspace: self-managed, self-hosted, up to 50 users, with many premium capabilities included. Community is the open-source MIT edition for teams that have exceeded Starter's user limit and need only very basic capabilities; it is self-hosted only, supports up to 100 concurrent users and caps push notifications at 10,000 per month.

Mattermost's editions page also describes two free routes, but they are structured differently. Entry is the free mode of the commercial Enterprise Edition binary: it has all features of Enterprise Advanced with server-wide limits and omissions, and Mattermost says it is best suited for teams of fewer than 50 users. Team Edition is the MIT-licensed open-source binary intended for small teams, hobbyists or personal use under 250 activated users where single sign-on is not required.

The naming is still settling. Mattermost's pricing FAQ refers to organizations using Mattermost Free, while the editions page and the v11 forum announcement use Entry and Team Edition. That announcement also records that Team Edition's user limit dropped to 250 from 1,000 and that GitLab SSO was removed. If an older article or install script promises a 1,000-user free Mattermost with SSO, it describes a product that no longer ships in that form.

Rocket.Chat Community's boundaries are equally specific. The get-started page marks identity management (LDAP, SAML, OAuth, OpenID Connect), federation, read receipts and data loss prevention as unavailable on Community, and the authentication guide states that in Rocket.Chat 9.0.0 and later, LDAP, SAML and custom OAuth require a premium plan. Starter keeps those identity features. The Slack alternatives guide is a broader shortlist; this article is about which free tier survives your actual requirements.

User Caps Are Measured Differently

Rocket.Chat's documentation makes an unusually clear distinction: Starter limits how many users you can add to the workspace, while Community limits how many users can be connected at the same time. A 60-person company therefore exceeds Starter's 50-user cap even if only 30 people are online, but fits Community's 100-concurrent-user ceiling. Rocket.Chat says that at the Starter limit the workspace is restricted from adding new users while existing users and data remain accessible.

Mattermost counts activated users. Its pricing FAQ defines a seat as an activated user registered on a specific server and not deactivated; deactivated users keep history and preferences. Team Edition's 250-user scope and Professional's positioning for teams of up to 250 users both use that activated-user concept. Entry's limits are not a hard user count but usage ceilings: the editions page lists 10,000 channel messages of viewable history across all channels, with older messages remaining in the database but not viewable or searchable.

A worked example shows why the measurement matters. A 45-person team with 10 occasional contractors has 55 accounts. On Rocket.Chat Starter that is over the 50 added-user cap unless some accounts are not created; on Community it is fine as long as fewer than 100 are connected simultaneously, but LDAP sign-on disappears. On Mattermost Team Edition all 55 are well under 250, but there is no SSO. On Entry the user count is not the gate; the 10,000-message history window is, and a chatty 55-person team can reach it in weeks. The remote-team tool guide explains why history is usually the first thing people miss.

Mattermost marks several Entry limits—Board cards, Playbook runs, Agent queries, 40-minute calls and 10,000 push notifications per month—with the note that limits will take effect in a future release. Treat them as the documented intent, not as proof of today's enforcement or absence. Do not plan a production rollout around a limit that may change at the next upgrade; plan around the licensed tier you can actually buy.

Guest Accounts and External Collaborators

Mattermost's guest accounts guide says guests in exactly one active channel are treated as single-channel guests: they do not count toward the primary paid seat count and are free up to a 1:1 ratio with licensed seats. Guests in multiple channels count as paid active users. Exceeding the ratio produces soft warnings rather than a hard block. The editions page places guest access under Professional, so this model applies to a paid server, not to Team Edition.

Translate that into numbers before promising clients a free login. With 20 licensed seats, up to 20 single-channel guests cost nothing extra; the 21st triggers warnings; and a client contact added to two project channels becomes a paid active user regardless of the ratio. An agency with 12 staff and 30 client contacts cannot keep all 30 free on a 12-seat license, and any client who needs two channels changes the count again.

Rocket.Chat approaches external collaboration partly through federation. Its pricing page describes federation with Rocket.Chat and Matrix servers so partners collaborate in shared channels while each organization keeps its own infrastructure, and the native federation documentation carries a premium badge. On the free tiers, the get-started page lists federation as unavailable for Community; the plans page lists Starter's capabilities without federation. If cross-company channels are the requirement, both products point you toward a paid plan.

Push Notifications: The Hidden Monthly Meter

Mobile notifications are the first place self-hosters discover a quota. Rocket.Chat's push documentation says notifications sent through its gateway count toward the workspace's monthly limit and that the official mobile apps work only with the Rocket.Chat gateway. The plans page sets Community at 10,000 per month and Starter at unlimited. Hiding message content from Apple and Google—ID-only push—is a premium-plan feature in Rocket.Chat's security overview.

Mattermost's push settings documentation says Enterprise, Professional and Cloud customers can use the Hosted Push Notification Service, while non-commercial self-hosted customers can use the free, basic Test Push Notifications Service. Entry's editions entry lists 10,000 push notifications per month among the limits scheduled for a future release, and ID-only push notifications sit in the Enterprise feature list.

Estimate the meter before choosing. Thirty people receiving an average of 15 mobile notifications each per working day generate 30 × 15 × 22 = 9,900 notifications in a 22-day month, which sits just under both 10,000 caps. A busier month, a second device per person or an incident channel pushes the same team over. Rocket.Chat's documentation did not state what happens to messages after the cap is exceeded, so test the behavior in a staging workspace rather than assuming notifications queue or degrade gracefully.

Calls, Playbooks, Boards and Integrations

Mattermost's Calls deployment guide distinguishes tiers: Entry or Team Edition get 1:1 calling and screen sharing up to 40 minutes, Professional adds group calling and screen sharing with no time limit, and recording or the dedicated RTCD service belong to Enterprise. Its pricing page describes group calling up to approximately 50 concurrent participants per self-hosted server. Rocket.Chat's plans page lists Jitsi and BigBlueButton integrations on Community, and adds Pexip, Google Meet and Zoom on Starter and paid plans; its own VoIP add-on is a paid extra.

Workflow tooling is a Mattermost differentiator with caveats. Playbooks and Boards are included in Entry under the future limits of 5 active Playbook runs per month and 1,000 Board cards, and the Boards installation page says the plugin is in maintenance mode, is not enabled by default for new Enterprise instances and is no longer receiving new features. Do not select Mattermost for Kanban boards without reading that notice; the project management tool guide covers dedicated alternatives.

Apps are where Rocket.Chat's free tiers diverge sharply. The marketplace documentation allows unlimited marketplace apps on Starter and premium plans, limits Community to five public apps and zero private apps, and says private apps on Community workspaces are disabled by default from version 7.0. The get-started page instead says Community is capped at three private apps and five marketplace apps—an official conflict this article records rather than resolves. Marketplace access also requires registering the workspace with Rocket.Chat Cloud regardless of plan.

Mattermost's plugin platform is available across editions through the plugin management guide, with pre-packaged Jira, GitHub and GitLab integrations listed under Professional on the editions page. Webhooks, slash commands, the REST API and an MCP server appear in the shared feature list on its pricing page. The no-code automation guide is useful if your integrations will be built outside either chat product.

Encryption, Retention and Compliance Controls

Rocket.Chat lists end-to-end encryption among Starter's security capabilities, and its E2EE user guide documents the trade-offs plainly: encrypted messages do not appear in search results, encrypted content cannot be audited or monitored, bots may be unable to access it, and encryption is not available for public channels. Supported scopes are direct messages, discussions, private channels and private teams. Mattermost's documentation reviewed here does not describe an end-to-end encryption feature; its security model relies on transport encryption, access controls and infrastructure hardening.

Retention defaults differ. Rocket.Chat's retention policy guide says messages are never deleted by default, supports global and per-room pruning, and keeps deleted messages in a trash collection for 30 days. Mattermost uses soft deletion by default, where user-deleted messages leave the interface but persist in the database; its data retention policy for global and custom rules is an Enterprise capability, and Entry explicitly excludes compliance features including data retention.

Compliance exports, legal hold and audit tooling are paid in both products. Mattermost's compliance export is for Enterprise customers and supports CSV, Actiance, Global Relay and Proofpoint formats, while noting that Playbooks and Boards data are not included. Rocket.Chat's security overview places the Message Auditor, custom roles and device management on premium plans. A free tier is not a regulated-industry archive; the password manager guide is a reminder that open-source does not mean every control is free.

Exports and Portability Before You Commit

Rocket.Chat offers user-facing export without a stated plan gate. The room options guide documents exporting messages by email as HTML, as an HTML or JSON file by email, or as a JSON download, and the user data download feature lets an individual request their own data when an administrator enables it. These are per-room and per-user tools, not a documented one-click full-workspace archive with attachments.

Mattermost's self-service equivalents are administrative. The channel export slash command produces CSV and is listed under Enterprise on the editions page, and compliance export is Enterprise as well. A command-line bulk export exists for administrators with server access; its documentation reviewed here does not state a plan gate, but it is an operator tool rather than an end-user button. On Team Edition or Entry, plan on database-level backups as your primary portability route.

Neither export format proves a lossless move to the other product or back to Slack. Threads, reactions, file attachments, pinned items, custom emoji and integrations each need their own check. Before migrating a live team, export a small real channel, re-import or reconstruct it in isolation, and compare counts. The free cloud storage guide explains why file synchronization is not a backup; the same distinction applies to chat archives.

Deployment Requirements: MongoDB Replica Sets vs PostgreSQL

Rocket.Chat's system requirements call for MongoDB 8.0 or later for Rocket.Chat 8.x, with a three-member replica set strongly recommended and GridFS file storage not recommended. The published Starter minimum is 2 vCPU, 4 GiB RAM and 20 GiB for the application plus 2 vCPU, 4 GiB and 10 GiB for MongoDB, described as serving up to 500 concurrent users. The Docker Compose guide points to the official compose repository and notes that each version is supported for six months after release.

Mattermost's hardware requirements are lighter for small teams: 1 vCPU and 2 GB RAM for 1 to 1,000 users, and 2 vCPUs with 4 GB for 1,000 to 2,000. It requires PostgreSQL 15.0 or later, with MySQL support deprecated from v11. Its container deployment guide warns that the Docker Compose method should not be used in production because it does not support clustered or high-availability deployments. Treat both vendors' compose files as evaluation tooling.

Those requirements translate into an operating budget. Assume a $12 per month server for Mattermost on a single node and $24 per month for Rocket.Chat split across application and database capacity, plus $3 per month for off-server backups, $15 per year for a domain and $10 per month for monitoring or a managed database add-on. Annual cash cost is 12 × ($12 + $3 + $10) + $15 = $315 for Mattermost and 12 × ($24 + $3 + $10) + $15 = $459 for Rocket.Chat. These are invented planning inputs, not provider quotes; the Vultr vs Hetzner comparison shows how real instance prices vary by region.

Labor dominates. If one administrator spends four hours on initial deployment and two hours per month on upgrades, backups and incident response at $35 per hour, labor is (4 + 24) × $35 = $980 for the first year—more than double either infrastructure figure. Rocket.Chat's six-month version support window and Mattermost's monthly release cadence both imply regular upgrade work. The hosting and DevOps category can help pick infrastructure, but it cannot remove the operator role.

Licensing: What Open Source Means in Each Codebase

Rocket.Chat's repository license states that content under the ee directories is licensed under a separate enterprise license while everything outside those directories is available under the MIT license. The Community edition is the MIT build; Starter and premium features are unlocked by workspace registration and licensing rather than by a different download. Open source here means the core, not the premium folders.

Mattermost's license file says compiled versions produced by Mattermost, Inc. are licensed under MIT, while the source is offered under the GNU AGPL v3.0 or a commercial license, with administrative tools and the web app under Apache 2.0. The Enterprise Edition binary is distributed under a commercial license, and Entry is that binary running without an activated subscription. The editions page notes a monthly compiled MIT release and a trademark policy requiring the Mattermost wordmark to be replaced in community builds.

The practical consequence is that forking or modifying Mattermost's source engages AGPL obligations for derivative works, whereas running the unmodified compiled Team Edition is MIT. Rocket.Chat Community is MIT throughout, but using premium features means accepting Rocket.Chat's plan terms. Neither license removes your obligations to users and regulators; the SaaS evaluation checklist has a place to record who in your organization owns license compliance.

Paid Plans: Seat Rules When the Price Is a Quote

Because neither vendor publishes a per-seat price, compare contract mechanics instead. Mattermost's pricing FAQ says Professional and Enterprise licenses are sold as prepaid annual subscriptions by seat, that exceeding the seat count triggers quarterly true-forward purchases prorated for the remaining term, and that each server—including federated servers and non-production environments—requires its own license, while a high-availability cluster sharing one database counts as one server. Mattermost Cloud is described as a single-tenant Enterprise service arranged through sales.

Rocket.Chat's plans page presents Commercial, Government and Defense as premium plans with custom user counts, premium and dedicated hosting, and add-ons such as Sovereign AI, VoIP, Mission Critical support and professional services. FIPS 140-3 operation is a license add-on on Government and Defense. Starter's documentation says an upgrade to a premium plan does not require data migration, and that downgrading to Community is possible when only basic capabilities are needed.

Ask both vendors the same questions in writing: the seat definition and whether inactive or deactivated accounts count, the treatment of guests, the number of licensed servers including staging, the renewal and true-forward rules, support hours and response targets, and the data-export rights at termination. Record the answers alongside the SaaS spending worksheet so the quote can be compared with the infrastructure and labor budgets above rather than with a headline that no longer exists.

Which Self-Hosted Chat Fits Your Team?

Start with Rocket.Chat Starter when you have 50 or fewer accounts, need LDAP or SAML sign-on, read receipts, retention rules and unlimited push without paying, and can operate MongoDB with a replica set. Start with Mattermost Entry when a team under 50 wants Playbooks, Calls, Boards and AI agents in one self-hosted package and accepts the 10,000-message viewable history and future usage limits. Prefer Mattermost Team Edition for a larger hobbyist or internal community of up to 250 activated users that does not need SSO, and Rocket.Chat Community only for non-production use that fits its 100-concurrent-user and app limits.

Move to a paid plan when compliance exports, retention policies, federation, guest ratios or supported upgrades become requirements—and get the quote before the pilot ends, because neither product publishes one. The right decision follows your first hard constraint: account count, identity provider, history, notifications or audit obligations. Validate it with a staging deployment, a real export and a written quote, not with a feature matrix or a claim that open-source chat is free to run.