Mattermost vs Rocket.Chat vs Zulip: which to choose

Mattermost vs Rocket.Chat vs Zulip: which fits your team

If your team is replacing Slack on its own infrastructure and needs SSO, audit trails or air-gapped operation, the right platform depends on how many users you have and which features you are willing to pay for. Mattermost suits channel-based chat that must scale with paid high availability and air-gapped tiers, Rocket.Chat suits small teams that can run on its free Starter plan of up to 50 users, and Zulip suits teams that want topic threading and SAML, LDAP and SCIM on the self-hosted server without an open-core split. Each platform has a different point where a feature moves behind a subscription, so the verdict turns on user count and on which controls your auditors and security team require.

Start by listing the controls you must prove. For Mattermost, SSO over SAML, OIDC or OAuth and AD/LDAP user sync are included from the Professional plan, while high availability clustering and FIPS 140-3 compliance start at Enterprise, and air-gapped deployment sits in Enterprise Advanced. Rocket.Chat's free Starter plan includes LDAP and Active Directory authentication, single sign-on, multi-factor authentication and end-to-end encryption, but multi-instance designs, SAML user group mapping and tamper-evident audit trails sit on quoted paid plans. Zulip's self-hosted server includes SAML, LDAP and custom roles without a paid plan, so confirm with your own environment whether its SCIM and sync behavior meets your identity process before you rely on it.

Before you choose, confirm three things with each vendor in writing: the plan that includes each control in your list, the high availability and file storage rules that apply to your user count, and the upgrade cadence you can sustain. Mattermost publishes a monthly server release with support windows you must track, Rocket.Chat standard releases are supported for 6 months and LTS releases for 12 months, and Zulip Server 12.3 was published on September 21, 2026. Mattermost and Zulip both document imports from Slack and from each other's products, so a pilot with a few channels and a sample user set will show you how much migration work each option creates.

Which platform fits which scenario

This table maps common team situations to the platform that fits best, with the fact-based reason and the condition under which another option would win. Read each row against your user count, identity stack, network model and migration history, since those conditions decide the pick more than feature lists do.

Scenario	Best fit	Why, and when an alternative wins
Small team under 50 users that needs SSO	Rocket.Chat	The free Starter plan allows up to 50 users and includes LDAP and Active Directory authentication and single sign-on. Zulip's self-hosted server also includes SAML and LDAP without a paid plan, so Zulip wins if you prefer its threading model and can accept its mobile push limit of 10 users on the free Community plan.
Regulated enterprise needing high availability and FIPS 140-3	Mattermost	Mattermost lists high availability clustering and FIPS 140-3 compliance in the Enterprise plan, and HA requires shared storage such as S3, an S3-compatible service or NAS on each node. Rocket.Chat's paid plans list built-in redundancy and tamper-evident audit trails, so Rocket.Chat fits if its quoted plan matches your assessor's evidence needs. Confirm FIPS coverage with each vendor in writing.
Air-gapped network with no internet access	Mattermost	Air-gapped deployment is listed in the Enterprise Advanced plan, and Mattermost ships a single Linux binary on PostgreSQL. Rocket.Chat's air-gapped deployment is a paid-plan capability, so Rocket.Chat fits if you already hold a quoted plan that covers offline operation. Zulip's self-hosted path also avoids open-core splits, but confirm the offline update and push notification approach in your environment.
Team with heavy asynchronous discussion across time zones	Zulip	Zulip's topic-based threading is designed for both live and asynchronous conversations, which keeps long discussions readable after the fact. Mattermost and Rocket.Chat use channel-based conversations, so they win if your teams work mostly in short live exchanges and need channel structure more than topic threads.
Team migrating from Slack	Mattermost or Zulip, depending on the threading model you want	Zulip's help center documents imports from Slack, Mattermost and Rocket.Chat. Rocket.Chat's import tools support full Slack workspace exports, and Mattermost has its own migration guide from Slack. Choose by target model, then test the export on a copy of a real channel set before committing, and confirm how each tool maps users, threads and attachments.
Team that must keep mobile push working over time	Mattermost or Rocket.Chat on a current supported line	Rocket.Chat states that unsupported versions may lose the ability to connect with its official mobile and desktop clients, and its cloud services such as the push notification gateway stop after end of life. Mattermost publishes a monthly release cadence with dated support windows. Zulip's free Community plan limits mobile push to 10 users for most organizations, so choose Zulip only if that limit or a paid plan fits your headcount.
Teams that expect frequent upgrades with limited operations staff	Zulip or Mattermost on an Extended Support Release	Rocket.Chat standard releases are supported for 6 months and LTS releases for 12 months, which means more frequent upgrades. Mattermost offers Extended Support Releases, such as v11.7 with support ending 2027-05-15, which reduces upgrade frequency. Confirm the upgrade effort for your chosen tier with the vendor before you commit.

What each platform's license and paid editions include

Mattermost publishes its compiled server binaries under the MIT license, its source for custom builds under AGPL v3.0 and its admin tools and configuration files under Apache 2.0, according to the project's LICENSE.txt. The paid layer is a set of seat subscriptions. Professional, Enterprise and Enterprise Advanced are prepaid annual plans priced by seat licenses, and the pricing page lists no public prices, so you must request a quote. SSO through SAML, OIDC and OAuth and AD/LDAP user sync are included from Professional. High availability clustering and FIPS 140-3 compliance start at Enterprise, and air-gapped deployment is in Enterprise Advanced.

MIT binaries: Running the published server binary carries the MIT terms, but the paid features are gated by the subscription, not by the license.
AGPL source: Teams that build a custom server from source work under AGPL v3.0, and the commercial alternative from Mattermost, Inc. is a separate contract to confirm.
Professional plan: SSO and AD/LDAP sync are the first features you pay for, so SSO costs are a seat-based line item from day one.
Enterprise plan: High availability and FIPS 140-3 compliance require this tier, along with the cluster file storage you must provide.
Enterprise Advanced plan: Air-gapped operation is only in this tier, so confirm whether your network needs it before you compare seat prices.

Ask Mattermost in writing which features each tier includes at your version, how seat counts are measured and whether support windows match your upgrade schedule.

How each platform's architecture shapes the hosting footprint

Mattermost runs as a single Linux binary on PostgreSQL, and its footprint grows in steps. A single server is the simplest case, but high availability is only available on the Enterprise and Enterprise Advanced plans and needs redundant application servers, redundant database servers and redundant load balancers. Every node must mount shared file storage, either Amazon S3, an S3-compatible service or NAS, because local file storage will not work correctly and risks file corruption. Read replicas and search replicas can spread load, with writes still going to the primary database. Before you size a cluster, confirm with Mattermost which plan covers your redundancy design and what your storage backend costs to run. On upgrades, plan around the monthly binary release on the 16th and the support windows: v11.11 ends support on 2026-12-15, and the v11.7 Extended Support Release runs to 2027-05-15. A team that stays on a supported line has a predictable upgrade calendar.

Rocket.Chat is a Node.js application on a MongoDB 8.x replica set, and its scale-out path is the most structured of the three. Version 8.x requires MongoDB 8.0 or later as a replica set, with a three-member set strongly recommended for high availability, so the team must operate a MongoDB cluster alongside the chat application. Rocket.Chat's reference architectures describe one instance with a MongoDB replica set up to 500 concurrent users, multiple load-balanced instances linked by NATS above 500, and microservices on Kubernetes with the official Helm chart above 5,000. The multi-instance and microservice designs require a paid plan, so a team that expects to pass 500 users should price that plan before choosing the topology. Upgrade pressure is the sharpest of the three: standard releases are supported for 6 months and LTS releases for 12 months, and unsupported versions may lose the ability to connect with the official mobile and desktop clients.

Zulip gives the smallest footprint to start with, and its operational load is mostly routine upkeep. The README describes self-hosting directly on Ubuntu or Debian, in Docker through docker-zulip, or with prebuilt images for DigitalOcean and Render. Its production documentation lists the requirements, so the team should confirm the current database, memory and storage needs for its expected user count there before sizing hardware. Zulip Server 12.3 was published on September 21, 2026, following 12.0 on April 27, 2026, so the team should plan upgrades against that release cadence and confirm which versions remain supported. Because the self-hosted server has no open core split, high availability and read scaling are not gated behind a license, but the team must still design and test those layers itself, which is the main effort to confirm in a quote.

Which SSO and compliance features need a paid plan

Identity and compliance features are where the three platforms differ most on price. Zulip's self-hosted server includes SAML and LDAP without a paid plan, Rocket.Chat's free Starter plan covers several identity controls up to 50 users, and Mattermost gates most of its identity and compliance features behind subscriptions. Each card below states what is free, what is paid, and what to confirm against current plan terms.

SSO and AD/LDAP sync

Single sign-on and directory sync decide whether accounts follow your joiner and leaver process. Zulip's self-hosted server includes SAML and LDAP, including Active Directory data sync, without a paid plan. Rocket.Chat's free Starter plan includes LDAP, Active Directory and single sign-on, while its paid plans add LDAP and SAML group mapping. Mattermost includes SSO (SAML, OIDC, OAuth) and AD/LDAP user sync from its Professional plan. Confirm which SSO protocols and group mappings your identity provider needs on the plan you intend to buy.

Multi-factor authentication

MFA is a baseline control for any chat system that holds internal and customer-related conversations. Rocket.Chat includes multi-factor authentication in its free Starter plan, which is the only one of the three that the supplied facts place on a free tier with MFA. Mattermost and Zulip are not confirmed for MFA in the supplied facts. Ask each vendor whether MFA is built in, which methods it supports (such as TOTP or hardware keys), and whether it depends on your SSO provider enforcing it.

Audit trails and data exports

Audit trails and exports are what auditors and legal teams ask for first. Rocket.Chat's paid plans list tamper-evident audit trails covering messages, files and sessions. Zulip's Business plan adds data exports for self-hosted deployments, so confirm whether exports meet your retention and legal hold needs. The supplied facts do not confirm an equivalent audit trail feature for Mattermost, so ask Mattermost which compliance exports and audit logs its current plans include, and whether tamper evidence is part of them.

High availability

High availability is a paid capability on two of the three platforms, and the storage design behind it adds cost. Mattermost high availability is available only on its Enterprise and Enterprise Advanced plans, and it requires shared file storage on Amazon S3, an S3-compatible service or NAS on every node. Rocket.Chat lists built-in redundancy with automated failover in its paid plans and recommends a three-member MongoDB replica set. Confirm whether Zulip's self-hosted plans include any HA design, since the supplied facts do not cover it.

Air-gapped deployment

Air-gapped operation matters for networks with no internet access, such as defense or certain critical infrastructure. Mattermost places air-gapped deployment in its Enterprise Advanced plan, and Rocket.Chat treats it as a paid-plan capability that is not available on Starter. Zulip's supplied facts do not address air-gapped operation, so ask Zulip how it handles offline installs, updates and push notifications. Whichever you choose, confirm how license activation, updates and certificates work without outbound connections.

SCIM provisioning

SCIM automates account creation and removal from your identity provider, which reduces stale access after staff leave. Zulip's production documentation covers SCIM, and its self-hosted server carries no open-core restriction on that feature. The supplied facts do not confirm SCIM for Mattermost or Rocket.Chat, so ask both vendors whether SCIM is included, on which plan, and whether it covers user deactivation as well as creation. Test deprovisioning in a staging instance before you rely on it.

Mobile push limits and release support windows

Mobile push is the first limit to check, and it differs by product. Zulip's free self-hosted Community plan includes all features but limits mobile push notifications to 10 users for most organizations. The Basic plan, priced at $3.50 per user per month billed monthly, removes that cap with unlimited mobile notifications. Rocket.Chat's push path works differently: its push notification gateway is a cloud service, and it stops working once a version reaches end of life. Rocket.Chat also warns that unsupported versions may lose the ability to connect with the official mobile and desktop clients. Before you pick a plan, count the users who will install the mobile app, confirm with each vendor how their push delivery is provided for a self-hosted server, and test notifications on a staging instance that matches your network egress rules.

Support windows set the upgrade pace, so map them before the first production go-live. Mattermost publishes a new server binary on the 16th of each month, and each release carries its own end-of-support date. v11.11 was released on 2026-09-16 with support ending 2026-12-15, and v12.0 was released on 2026-10-16 with support ending 2027-01-15. Its Extended Support Release, v11.7, was released on 2026-05-15 with support ending 2027-05-15, which suits teams that cannot upgrade monthly. Rocket.Chat standard releases are supported for 6 months and LTS releases for 12 months. Zulip's server release history shows 12.0 on April 27, 2026 and 12.3 on September 21, 2026, but confirm its current support policy on the releases page before you commit to a cadence.

Build an upgrade calendar from the end dates, not the release dates. Record each platform's current support end date, then schedule a test upgrade in a staging copy of the database and file store at least one cycle before that date. For Mattermost, that means a monthly test on the 16th for standard releases or a single yearly test for the ESR line. For Rocket.Chat, a 6-month standard line means two upgrade windows per year, while an LTS line means one. Ask each vendor for its written support policy and check that mobile and desktop clients are tested against the version you plan to run. Treat any gap between a support end date and your next window as a risk to plan for.

How much does it cost to run and migrate

What does a Mattermost, Rocket.Chat or Zulip quote depend on?

The quote depends mostly on the number of users, whether you need high availability, and whether the deployment must run air-gapped. Mattermost sells Professional, Enterprise and Enterprise Advanced as prepaid annual subscriptions based on seat licenses, and its pricing page lists no public prices, so you must ask sales for a figure. Rocket.Chat's paid Commercial, Government and Defense plans are priced by quote, and air-gapped deployment sits only on paid plans. Zulip's self-hosted Business plan lists $6.67 per user per month billed annually or $8 billed monthly, with a 25-user minimum, and Enterprise pricing is custom. Ask each vendor to price the same user count, the same HA scope and the same support level, and to state what recurs each year.

How much effort does a high availability cluster take to run?

A high availability cluster adds moving parts, so expect more operating work than a single server. Mattermost HA needs redundant application servers, redundant database servers and redundant load balancers, and it is available only on Enterprise and Enterprise Advanced. Its shared file storage must be Amazon S3, an S3-compatible service or NAS mounted on each node, because local storage risks file corruption. Rocket.Chat 8.x requires MongoDB 8.0 or later as a replica set, with three members strongly recommended for high availability, and its multi-instance designs need a paid plan. Your effort depends on the database and storage you already run, your monitoring, and how often you upgrade. Confirm these with each vendor against your own environment.

Can our team self-host this without a partner?

Many teams can self-host a single-instance deployment with in-house staff, but the answer depends on your skills and your upgrade cadence. Mattermost runs as a single Linux binary with PostgreSQL, and Zulip can run directly on Ubuntu or Debian, in Docker or on prebuilt images. Rocket.Chat needs MongoDB as a replica set and a Node.js runtime bundled in its image. Upgrades are the recurring workload: Mattermost ships binaries on the 16th of each month, Rocket.Chat standard releases are supported for 6 months and LTS releases for 12 months, and unsupported versions can lose connections to official mobile and desktop clients. If you want outside help, DeployOpen plans, implements, integrates, hardens, backs up, upgrades and supports self-hosted platforms in your own infrastructure under a written, fixed scope, and ongoing support is available as a retainer.

How long does a Slack migration take, and what drives the time?

The duration is driven by workspace size, the depth of history you keep, and how much identity mapping you must do, so ask each vendor and your partner for a timeline based on your export. All three platforms document Slack imports. Rocket.Chat supports full Slack workspace exports and Slack users from CSV. Zulip's help center covers importing from Slack, Mattermost and Rocket.Chat. Mattermost publishes its own Slack migration guide. Time usually grows with the number of channels and archived messages, with file attachments that must be moved, with users who need matching accounts in your directory, and with the number of test runs needed before cutover. Plan a trial import on a copy of the export before you commit to a date.

What does it cost to switch between these platforms later?

Switching later costs more than the license, because you must move history, users, integrations and habits. Rocket.Chat's import tools accept Slack exports and a CSV importer, and Mattermost data is moved by converting its export into CSV. Zulip documents imports from Mattermost and Rocket.Chat, which makes it a plausible destination, but the conversion work, identity mapping and bot or integration rewrites still fall on your team or partner. Topic-based threading in Zulip also changes how old channel conversations map onto streams and topics. Budget for a dual-run period, retraining, and re-validating SSO and retention settings. Ask any vendor or partner for a written scope that lists exactly which data, users and integrations move.

Which features need a paid plan, and what does that change in the budget?

The paid-plan line changes the budget more than seat count alone. In Mattermost, SSO (SAML, OIDC, OAuth) and AD/LDAP sync start at Professional, while HA and FIPS 140-3 compliance start at Enterprise and air-gapped deployment at Enterprise Advanced. In Rocket.Chat, the free Starter plan (up to 50 users) includes LDAP, Active Directory, SSO, MFA and retention, while LDAP and SAML group mapping, tamper-evident audit trails and automated failover are paid. Zulip's self-hosted server includes SAML, LDAP and custom roles without a paid plan, so its paid plans mainly add mobile push for more users and vendor support. Map your must-have controls to a plan before you request a quote.

What recurs every year, and what is one-time?

Subscriptions, hosting and staff time recur, while setup, migration and integration work are usually one-time, though they can return with each major upgrade. Mattermost and Rocket.Chat paid plans are annual or quoted subscriptions, and Zulip's Business plan is billed per user per month. Infrastructure for servers, managed databases, S3-compatible storage and backups recurs in your own cloud or data center. The one-time items are discovery, configuration, identity setup and data import. Ask each vendor for a quote that separates license fees, support tiers, and any renewal or true-up rules, and ask your implementation partner for a fixed-scope statement of deliverables before work starts.

A practical evaluation path before you buy

This sequence turns the comparison into a shortlist decision your team can defend, by testing user load, paid feature needs, migration effort, upgrade capacity and vendor pricing against the same written requirements for each platform.

Confirm user count and peak concurrency
Platform or infrastructure leads count named users, active daily users and the peak number of simultaneous connections across all channels or streams. Rocket.Chat's free Starter plan allows up to 50 users and its free Community workspace allows up to 100 concurrent users, so a team near either figure should record that now. Mattermost and Zulip plan tiers are sized by seats, so the same count feeds their quotes. Done when you hold one number for total users and one for peak concurrency, and you know which of the three architectures (single instance, multi-instance or microservices for Rocket.Chat, HA cluster for Mattermost) your load points toward.
List required SSO and compliance features
The security or identity lead writes down each login and audit requirement: SAML, OIDC or OAuth, AD or LDAP user sync, SCIM provisioning, MFA, group mapping, message retention, audit trails and data exports. Check each item against the sources. Mattermost includes SSO and AD/LDAP sync from its Professional plan, and lists FIPS 140-3 compliance and HA clustering from Enterprise. Zulip's self-hosted server includes SAML, LDAP and SCIM with no paid gate, but its Basic and Business plans are the tiers for mobile push and vendor support. Rocket.Chat's Starter plan includes LDAP, SSO and MFA, while audit trails and user group mapping sit in paid plans. Done when every requirement is marked as free, paid or unconfirmed, with the plan name beside each paid item.
Check mobile push and support against each plan
The team lead confirms how many people will use mobile clients and whether they need push notifications. Zulip's free Community plan limits mobile push notifications to 10 users for most organizations, while its Basic plan includes unlimited mobile notifications. Rocket.Chat says unsupported versions may lose the ability to connect with its official mobile and desktop clients. Ask Mattermost which push path applies to your self-hosted build and whether it depends on a subscription. Done when you have a written answer for each vendor on mobile push, the plan that supplies it and the support tier attached to it.
Test an import of a sample channel set
An administrator exports a small, representative set of one or two channels, with users and attachments, from your current Slack workspace. Zulip's help center documents imports from Slack, Mattermost and Rocket.Chat. Rocket.Chat imports full Slack exports and Slack users from CSV, but Mattermost data reaches Rocket.Chat only after conversion to CSV. Mattermost's own Slack migration guide covers its path. Run each import into a test instance, then check that channels, threads, message history, user mapping and file links survive. Done when the team signs off on a list of what was lost or changed for each platform, because topic threading in Zulip maps to channel threads differently than in the other two.
Confirm the release calendar against your upgrade capacity
The platform owner lines up each vendor's release and support windows with your change calendar. Mattermost publishes server binaries on the 16th of each month, and its ESR v11.7 supports until 2027-05-15, while non-ESR releases such as v11.11 have a shorter window. Rocket.Chat standard releases are supported for 6 months and LTS releases for 12 months, and an end-of-life version stops receiving security fixes and cloud services. Zulip Server 12.3 followed 12.0 on the GitHub releases page. Done when you know which release line you will run, how often your team can apply upgrades in a test environment, and who owns each upgrade.
Get a written quote and an itemized scope
Procurement requests a written quote from Mattermost and Rocket.Chat, and a Zulip Business or Enterprise quote if you need more than the published self-hosted tiers. Mattermost and Rocket.Chat publish no fixed prices, so ask each for seat counts, plan names, included support and any air-gapped or HA charges. Zulip's Business plan is published at $6.67 per user per month billed annually or $8 billed monthly, with a 25-user minimum, and its Enterprise pricing is custom. Separately, request a fixed-scope proposal from DeployOpen for hosting, migration, hardening and support, which DeployOpen quotes from written scope. Done when you have side-by-side quotes that list seats, plans, support terms, one-time setup costs and recurring fees.

What implementing each platform involves

Mattermost is the lightest install to start, but the high availability work is where the effort sits. A single-node deployment runs as one Linux binary on PostgreSQL, and a team can stand it up with the standard server deployment planning steps before deciding on a Kubernetes Operator or a Linux install. Identity is the first real decision. SAML single sign-on and AD/LDAP user sync are plan-gated, so the engineering team should confirm the plan before building the SAML connection to Keycloak or Authentik. If the design calls for high availability, plan shared file storage on Amazon S3, an S3-compatible service or NAS mounted on each node, because local file storage will not work correctly in a cluster. Data import from Slack is documented in the migrate-from-slack guide, which a team should test against a copy of its export before cutover.

Rocket.Chat's work centers on the database and the deployment shape. Rocket.Chat 8.x requires MongoDB 8.0 or later running as a replica set, and a three-member replica set is strongly recommended for high availability, so the platform team owns a database tier that many organizations do not yet run. The official Docker image and Helm chart bundle Node.js, which simplifies packaging but still needs a load balancer, TLS and backup design around them. The reference architectures show that multi-instance and Kubernetes designs need a paid plan, so confirm the target user count before choosing the topology. For imports, the team should convert Mattermost or other exports into the CSV format, because Rocket.Chat's importers cover full Slack exports and CSV sources.

Zulip is the simplest to host on a single server and needs the most attention to its identity setup. The README describes direct installs on Ubuntu or Debian, a Docker path through docker-zulip, and prebuilt images for DigitalOcean and Render. LDAP with Active Directory synchronization, SAML including IdP-initiated SSO and Single Logout, and SCIM are documented production features, with setup guides for Keycloak and Authentik as SAML providers. Import tooling covers Slack, Mattermost and Rocket.Chat. For any of the three platforms, DeployOpen would plan the target architecture, harden the hosts and identity connections, document the runbooks and support the platform under a fixed scope agreed in writing before work starts. Ongoing upgrades and support are available as a retainer, and the quote follows from that written scope.

How DeployOpen helps you choose and implement

DeployOpen plans and implements self-hosted open-source platforms inside your own cloud accounts, data centers or air-gapped networks, so the choice between Mattermost, Rocket.Chat and Zulip is tested against your identity, compliance and user-count requirements before any build starts. Engagements are fixed-scope, with scope, deliverables and timelines agreed in writing first.

How we scope

We confirm your user count, SSO and directory needs, and which features must work without a paid plan.
We map SAML, LDAP, SCIM and compliance requirements to each platform's edition and plan terms.
The written scope lists deliverables, timelines and which licensing or plan decisions remain with your team.

How we build

We deploy the chosen platform in your infrastructure, including database choice and file storage for high availability.
We configure identity integration, mobile push considerations and retention settings against the agreed requirements.
We test the deployment, then run any import from Slack, Mattermost or Rocket.Chat as a scoped, verified step.

How we hand over

We document the architecture, configuration, identity mappings and the upgrade path for the release line you run.
We deliver the runbook for backups, restores and version upgrades so your operators can run the platform independently.
We walk your administrators through handover and record which features depend on a paid subscription.

How we support

Ongoing support, upgrades and continuous testing are available as a retainer after handover.
Retainers can cover tracking of support windows and patch cycles for the Mattermost, Rocket.Chat or Zulip release you run.
Ask any provider, including us, to confirm plan entitlements and release support dates in writing before you commit.

Mattermost vs Rocket.Chat vs Zulip