Slack vs Mattermost: Which Is right for your team?

Slack and Mattermost are both built for team communication, but they focus on different priorities: usability and speed vs security and control.

Mattermost is an open-source platform that keeps conversations and data entirely under your organisation’s control. If your team works under strict regulations, operates in air-gapped environments or needs to run collaboration software on its own servers, Mattermost gives you that level of ownership.

Slack is a cloud-based work operating system where teams share information, make decisions and move projects forward – with messaging, AI and app integrations all in one place. If your team juggles multiple tools and needs everyone aligned across departments and time zones, Slack is built for that.

Here’s how the two platforms compare.

Slack vs Mattermost at a glance

While both Slack and Mattermost help teams stay connected and productive, each platform is designed around a distinct philosophy – one prioritising ease and automation, the other emphasising control and customisation.

Slack gives teams a single place to communicate, connect their tools and get work done without managing any infrastructure. Built-in AI helps surface answers, Recap conversations and automate routine work, and Slackbot acts as a personal AI agent that can prep you for meetings, summarise threads and pull insights from connected apps.

Mattermost is built for organisations that need full authority over their data and platform. It runs on-premises, in private clouds or in air-gapped networks. The open-source codebase lets teams shape the platform around their workflows.

What Slack is great at

In Slack, every conversation, file and decision lives in one searchable place, organised by topic, team or project. Your team can go from a team chat thread to a shared doc to a live huddle without switching tools, and threaded channels keep async collaboration organised, even across time zones.

Information from your project trackers, CRM system and developer tools directly flows into your conversations, with no app switching required. With 2,600+ integrations and Workflow Builder’s no-code automation, your team spends less time toggling between tabs and more time on the work that matters.

New team members can join a Slack workspace and start collaborating within minutes. The interface is intuitive enough that most people pick it up on their own. And everyone, including external partners, can follow the work happening across the organisation through public channels, shared canvases and secure collaboration with Slack Connect.

What Mattermost is great at

Mattermost lets your organisation keep full ownership of its messaging data. You run the platform on your own servers or in a private cloud, so nothing leaves your infrastructure. Organisations in defence, finance, healthcare and government use Mattermost in air-gapped or classified networks where vendor-hosted SaaS platforms cannot operate.

The open-source codebase is publicly auditable, and engineering teams can modify the platform, build custom plug-ins or integrate with their existing tooling without waiting for vendor approval. Mattermost also builds structured playbooks directly into the messaging experience – teams managing incident response or release cycles get predefined checklists and automation steps right alongside their conversations.

Slack vs Mattermost: Interface and user experience

Slack and Mattermost both have a sidebar-and-channel layout, but the day-to-day experience reflects who each platform was designed to serve. Slack is built for broad organisational adoption, while Mattermost is tuned for technical and operations teams.

• Navigation and discoverability. Among office chat apps for teams, Slack stands out for putting channels, threads, apps and search in a single sidebar – features like canvas, huddles and bookmarks are easy to find without training. Mattermost organises its workspace around channels, playbooks and calls. The layout maps naturally to engineering and operations workflows but may take more orientation for teams outside those roles.
• Onboarding and setup. A new team can be up and running in Slack within minutes, with no technical setup required. Mattermost’s self-hosted model means that your IT team handles server provisioning, database configuration and ongoing maintenance. That gives organisations full infrastructure control, though it does set a higher bar for getting started.
• Day-to-day usability. Slack surfaces conversations, files and app notifications in a unified activity feed with easy thread navigation and quick-switch shortcuts. Mattermost covers the same communication basics and adds structured workflows through playbooks, giving operations teams a built-in way to manage recurring processes alongside their conversations.

Slack vs Mattermost: Messaging and collaboration

At their core, Slack and Mattermost both organise conversations into channels and threads. The experience around that core structure – and what you can do without leaving the platform – is where they start to part ways.

Slack: Built for collaboration

Slack treats messaging as the starting point for broader collaboration. You can jump from a channel thread to a canvas to draft a proposal, start a huddle for a quick voice call, or record a clip to guide someone through a process. Threaded replies, scheduled messages and channel-level notifications make asynchronous communication a natural part of the workflow, helping distributed teams stay aligned across time zones.

Slack’s centralised workspace keeps discussions, decisions and context visible as your organisation adds people and departments. New employees find what they need without hunting across tools, and cross-functional teams stay aligned through shared channels and threaded updates.

Mattermost: Structured workflows and control

Mattermost has the added structure of playbooks – predefined checklists and automation steps that teams run directly inside the platform. Playbooks turn a discussion thread into a trackable workflow for incident response, release management and other repeatable processes. Built-in calls support audio and screen sharing, though video conferencing isn’t included.

The messaging interface reflects Mattermost’s focus on technical teams, with a streamlined layout that prioritises function and familiarity for developers and operations staff. Mattermost also offers AI-powered search and call transcription through its Agents feature, with the option to connect your own large language model (LLM) so that data stays within your deployment. Mattermost’s structured playbooks keep operational processes consistent as teams expand, though the self-hosted model means that your infrastructure needs to grow alongside your headcount.

Slack vs Mattermost: Integrations and extensibility

Instead of switching between apps to track down updates, your team can pull information from project trackers, CRM systems and developer tools directly into Slack conversations through 2,600+ integrations. Any team member can use Workflow Builder to set up automations without touching code. Slackbot responds to custom triggers, reminders and routine requests. Deeper customisation is available through Slack’s APIs and SDKs, which support full-featured app development.

Mattermost takes a more modular approach. A curated marketplace offers pre-built plug-ins for tools like issue trackers, code deployment services and video conferencing. Teams can also build custom integrations using webhooks, slash commands, APIs or custom plug-ins. No-code automation through third-party connector platforms adds another option for teams that want integrations without writing code.

Slack vs Mattermost: Security and compliance

Slack encrypts data both in storage and in transit and holds certifications including SOC 2, SOC 3, ISO 27001, HIPAA and FedRAMP. With Enterprise Key Management, organisations hold their own encryption keys and can cut off access on demand. Admins get granular controls over who can access what – including custom retention policies, data loss prevention and audit logs for compliance reporting.

On the Mattermost side, security centres on deployment control. Because the platform can run on-premises, in private clouds or in air-gapped environments, organisations maintain full ownership of their data. Nothing leaves their infrastructure unless they choose otherwise. Mattermost holds ISO 27001 and supports compliance frameworks, including HIPAA and FINRA. Admin controls include role-based permissions, AD/LDAP group sync and full access to server logs.

Either platform can satisfy regulated industries. The distinction is whether your security approach relies on a vendor’s managed infrastructure and certifications or on your own team’s direct control over the environment.

Slack vs Mattermost: AI capabilities

Slackbot, your personal AI agent in Slack, is ready to use from day one. It can prep you for meetings, catch you up on threads that you missed and pull together briefs from scattered discussions. It also analyses shared documents and schedules calls, drawing on your workspace’s full history for grounded answers. AI in Slack comes standard on paid subscriptions, and every AI feature runs on Slack’s own infrastructure – your data stays on the platform and isn’t used for model training.

Mattermost takes a private, sovereign approach to AI. Through the Agents feature, you get AI-powered search across your workspace and automatic call transcription, with the option to connect your own LLM. Because the AI runs inside your own infrastructure, you can adopt AI assistance without sending data to an outside service. You choose which model provider to connect and keep full control over how AI interacts with your data.

Slack vs Mattermost: Pricing and setup

Slack offers a free tier and paid subscriptions that range from small teams to enterprise-wide deployment. Setup takes minutes, AI features come standard on paid subscriptions, and Slack’s team handles all infrastructure and updates. As a scalable business communication platform, Slack requires nothing to install, configure or maintain on your end.

Mattermost’s free edition is self-hosted with no user limit, so you can try it out before committing. Paid subscriptions are per user per month, with professional and enterprise tiers available.

But bear in mind: Your team’s budget tells only part of the story – the real cost includes the time and effort to get up and running and keep things maintained. With Mattermost, your organisation also covers server infrastructure, IT staffing, ongoing maintenance and any custom development for integrations or plug-ins. When comparing the two, factor in not just the per-user price but the total investment of time, people and infrastructure that each platform requires.

When to choose Slack vs Mattermost

Every organisation is different. Your team’s unique priorities should drive this decision. Here’s how to think through it.

When to choose Slack

Slack is the stronger fit when you need fast setup, broad integrations and collaboration that works for every department. As a team collaboration tool, Slack puts messaging, AI and 2,600+ integrations at your fingertips, with nothing to install or maintain. Enterprise chat applications like Slack also give IT leaders the security and compliance tools they need without piling on extra work.

Whether your team has 5 people or 50,000, Slack grows with you. A marketing team launching a campaign, for example, can quickly create a project channel, connect their design and Analytics tools and keep stakeholders aligned across offices and time zones, all from day one.

When to choose Mattermost

Mattermost makes sense when you require self-hosting, full data control and your team has the technical resources to manage the deployment. Mattermost is purpose built for organisations that operate in classified environments, work under strict regulations or need air-gapped deployment. A defence contractor coordinating across secure networks, for instance, can run Mattermost entirely on its own servers with custom integrations into internal systems – something cloud-hosted platforms cannot support.

Is Slack better than Mattermost?

It depends on what your team needs. Slack is stronger for enterprise-level usability, speed and cross-team collaboration at any size. Mattermost is stronger for data control, self-hosted security and organisations that need to own every layer of their infrastructure. Most teams will find that Slack’s combination of usability, integrations and AI gives them a faster path to productive collaboration – but teams with the strictest regulatory or deployment requirements are more likely to gravitate toward Mattermost’s self-hosted model.

Deciding depends on your team’s priorities

Slack and Mattermost both help teams communicate, but they serve very different priorities. Slack gives teams a managed cloud platform where communication, AI and thousands of integrations work together from day one. Mattermost gives organisations full ownership of their data and deployment through self-hosted, open-source infrastructure. Your team’s working style, security requirements and appetite for managing infrastructure should guide the decision.

Get started with Slack and see what a work operating system can do for your team.

Curious how Slack compares to other cloud-based collaboration and communication tools? Take a look at our other comparison pages:

• Slack vs Google Chat
• Slack vs Microsoft Teams
• Slack vs Discord
• Slack vs Trello
• Slack vs Asana

Slack vs Mattermost FAQ