Mattermost vs Slack: Features, Security, Pricing and Deployment

Mattermost and Slack are both team messaging platforms built around channels, direct messages, threads and file sharing. The biggest difference is not the chat interface. It is how the platforms are deployed and managed.

Slack is a cloud-based service operated by the vendor. Mattermost can be self-hosted, deployed in a private cloud or used as a managed service. That difference affects data control, administration, security architecture and total cost of ownership.

For most organizations, the choice comes down to this:

• Slack is designed for teams that want fast deployment, a large integration ecosystem and minimal infrastructure management.
• Mattermost is designed for organizations that need self-hosting, private infrastructure, isolated deployment or deeper control over the communication stack.
• TrueConf is worth considering when self-hosted messaging needs to be combined with broader video conferencing and enterprise communications.

Mattermost vs Slack at a Glance

Criteria	Slack	Mattermost
Deployment	Cloud-based	Self-hosted, private cloud or managed cloud
Open source	No	Open-source components and self-hosted editions
Infrastructure management	Handled by Slack	Can be handled by the organization
Channels and threads	Yes	Yes
File sharing	Yes	Yes
Calls	Huddles	Mattermost Calls
Integrations	Large ready-made ecosystem	APIs, plugins, webhooks and technical integrations
AI	Built-in AI capabilities	Private AI and custom model integrations
Data control	Data hosted in vendor infrastructure	Can remain on customer-controlled infrastructure
Isolated deployment	No self-hosted option	Supported in suitable deployments

The biggest architectural difference is simple: Slack is SaaS, while Mattermost gives organizations the option to operate the server environment themselves. That difference matters more than most feature-by-feature comparisons.

Key Differences Between Mattermost and Slack

The two platforms overlap heavily in everyday messaging. Both support channels, direct messages, threads, file sharing, search, calls, integrations and administrative controls.

The difference becomes more important when you look at deployment, IT responsibility and extensibility. Slack reduces infrastructure work because the vendor operates the service. Mattermost gives the organization more control, but that also means more responsibility for deployment, monitoring, backups, upgrades and security.

This is why Mattermost often appears in technical, regulated and infrastructure-sensitive environments, while Slack is more commonly used as a general business collaboration service.

The Main Difference: SaaS vs Self-Hosted

Slack is delivered as a vendor-operated cloud service. Organizations create a workspace and use the platform without deploying the underlying server infrastructure.

Mattermost can be installed on infrastructure controlled by the organization. Depending on the deployment model, it can run on-premises, in a private cloud or in isolated environments.

Area	Slack	Mattermost
Server deployment	Not required	Required for self-hosting
Updates	Managed by Slack	Managed by the organization in self-hosted deployments
Backups	Part of vendor-operated service	Organization controls backup strategy
Infrastructure access	Limited to vendor model	Direct infrastructure control
Data location	Depends on vendor deployment options	Can be determined by the organization
Isolated network	No self-hosted edition	Possible in suitable deployments

Self-hosting is not automatically better. It gives the organization more control, but also creates more operational work.

Messaging and Collaboration

For day-to-day messaging, Slack and Mattermost are structurally similar. Both organize communication around channels, direct messages and threads. Both also support file sharing, search and team discussions.

Slack

Slack is designed for broad business use. Channels can be created for teams, projects, topics or customers. Threads keep discussions organized, while huddles add lightweight voice and video communication.

Its main strength is the surrounding ecosystem. Messaging is closely connected with apps, workflows and other business tools.

Mattermost

Mattermost also uses channels, direct messages and threads. The platform is more strongly associated with technical and operational workflows. It combines messaging with APIs, plugins and workflow-oriented tools that can be adapted to internal systems.

The bigger distinction is that the organization can host the platform itself.

Mattermost vs Slack: AI and Automation

AI is becoming a more important part of team messaging platforms.

Slack increasingly combines messaging with AI-assisted search, summaries, workflow automation and contextual assistance.

Mattermost takes a more infrastructure-oriented approach. Organizations can connect AI capabilities to internal workflows and, depending on the deployment, use privately controlled models or services.

Integrations and Extensibility

Slack has a large ecosystem of ready-made integrations. This is useful when a company already relies on cloud applications for project management, development, calendars, CRM or document collaboration.

Mattermost has a smaller ready-made ecosystem, but gives technical teams more flexibility to build or host their own integrations.

• APIs
• webhooks
• plugins
• custom bots
• internal applications

The practical distinction is straightforward. Slack is stronger when a company wants many integrations that work with minimal setup. Mattermost becomes more interesting when integrations need to connect with internal or privately hosted systems.

Security, Compliance and Data Control

Both platforms provide enterprise security features, but their security models differ.

Slack

Slack operates the infrastructure. The organization configures security, access and governance inside the vendor-managed platform. This reduces the amount of infrastructure work required from internal IT.

Mattermost

Mattermost can be deployed on infrastructure controlled by the customer. That gives the organization more influence over server location, network access, logs, storage and administrative policies.

The tradeoff is responsibility. The organization also needs to manage patching, backups, monitoring, hardening, capacity and recovery.

So the security difference is not simply that one platform is more secure than the other. It is about who controls and operates the infrastructure.

Open Source

Slack is proprietary software.

Mattermost includes open-source components and provides self-hosted deployment options. This matters most for organizations that need greater control over the application environment, custom plugins or server-side extensions, integration with internal systems, private infrastructure or more visibility into how the platform is built.

Open source does not automatically make deployment easier. In practice, it often provides more flexibility while also increasing the amount of technical work required.

User Experience and Administration

The user-facing experience is similar enough that people familiar with channel-based messaging can usually adapt to either platform. The bigger difference is administrative.

Area	Slack	Mattermost
Initial deployment	Quick workspace setup	Server deployment may be required
Infrastructure	Vendor-managed	Customer-managed for self-hosting
Updates	Vendor-managed	Administrator-controlled
Customization	Apps, workflows and workspace settings	Plugins, APIs and server customization
Admin workload	Lower	Higher in self-hosted environments

Slack reduces the amount of infrastructure work required from internal IT. Mattermost gives administrators more control over the platform itself. That tradeoff should be part of the product decision from the beginning.

Pricing and Total Cost of Ownership

A simple monthly price comparison is not enough. Slack and Mattermost have different cost structures because they use different deployment models.

Cost factor	Slack	Mattermost
Software	Subscription-based	Free and paid options depending on edition
Server infrastructure	Included in service	Required for self-hosting
IT administration	Lower	Higher
Updates and maintenance	Vendor-managed	Organization-managed
Scaling cost	Mainly tied to users and plans	Depends on licenses and infrastructure

For this reason, total cost of ownership is more useful than comparing only the advertised monthly price.

Migration From Slack to Mattermost

Migration matters because Mattermost is often considered by organizations already using Slack.

The technical migration may include users, channels, direct messages, message history, threads, files and permissions. But moving the data is only part of the work.

A company may also need to recreate integrations, bots, workflows, external collaboration processes, notification rules and application connections. For larger organizations, the integration layer may require more work than the chat migration itself.

Mattermost vs Slack for Different Use Cases

General Business Collaboration

Slack fits organizations that want a cloud-based communication platform with minimal deployment work and a large integration ecosystem. It is especially practical when teams already use many SaaS applications.

Software Development and DevOps

Both platforms can work well. Slack offers a large collection of existing integrations. Mattermost becomes more interesting when development tools and internal systems are hosted inside the organization’s own infrastructure.

Regulated Organizations

Organizations comfortable with vendor-managed cloud infrastructure may choose Slack. Organizations that need direct control over servers, data location or network access may prefer a self-hosted platform such as Mattermost.

Isolated Networks

Slack does not offer a self-hosted server. Mattermost can be used in environments where communication infrastructure needs to remain under organizational control.

Small Teams

Slack generally requires less infrastructure work. Mattermost can still make sense for a small technical team if self-hosting is an explicit requirement and the team already has the resources to maintain the server.

When TrueConf May Be a Better Fit

Slack and Mattermost are primarily team messaging platforms. Some organizations need the same environment to handle not only messaging, but also larger video meetings, calling and interoperability with existing communication systems.

TrueConf positions itself as a self-hosted Slack alternative that adds native video conferencing to team messaging.

TrueConf Server can be deployed on an organization’s own infrastructure and combines personal and group messaging, file sharing, audio calls, video conferencing, screen sharing, centralized user management and SIP/H.323 interoperability.

Mattermost is more focused on self-hosted team messaging and technical collaboration. TrueConf is oriented more toward unified communications, where messaging and video are part of the same internally managed platform.

Mattermost vs Slack vs TrueConf

Requirement	Slack	Mattermost	TrueConf
Cloud team messaging	Yes	Yes	Yes
Self-hosted messaging	No	Yes	Yes
Open-source components	No	Yes	No
Isolated deployment	No self-hosted option	Yes	Yes
Large app ecosystem	Strong	More focused	Enterprise-oriented integrations
Video conferencing	Huddles	Calls	Core platform capability
SIP/H.323 interoperability	No core focus	No core focus	Yes
Main focus	SaaS collaboration	Controlled team messaging	Unified communications

Frequently Asked Questions

What is the main difference between Slack and Mattermost?

The main difference is deployment. Slack is a cloud-based service operated by the vendor. Mattermost can be self-hosted, giving organizations more control over the server environment.

Is Mattermost a Slack alternative?

Yes. Mattermost is commonly evaluated as a self-hosted alternative to Slack, especially by organizations that need on-premises or private-cloud deployment.

Can Slack be self-hosted?

No. Slack is provided as a cloud service and does not offer a self-hosted server edition.

Is Mattermost open source?

Mattermost includes open-source components and also provides commercial editions for enterprise use.

Can Mattermost work in an isolated network?

Yes, depending on deployment and configuration. This is one of the main architectural differences compared with Slack.

Which platform has more integrations?

Slack has the larger ready-made integration ecosystem. Mattermost provides APIs, plugins, webhooks and other tools that can be useful when teams need custom or internally hosted integrations.

Which platform requires more IT resources?

Mattermost generally requires more internal IT resources when deployed on the organization’s own infrastructure. Slack’s infrastructure and platform maintenance are handled by the vendor.

Does Mattermost support AI?

Mattermost can integrate AI capabilities and privately controlled models, depending on the deployment. Slack also includes built-in AI features and workflow automation.

When should a company consider TrueConf instead?

TrueConf becomes relevant when an organization needs self-hosted messaging together with broader video conferencing and SIP/H.323 interoperability.

Conclusion

Mattermost and Slack solve many of the same everyday messaging tasks, but they are built around different operating models.

Slack is a vendor-managed cloud platform designed to reduce deployment work and provide immediate access to messaging, integrations, workflows and AI capabilities.

Mattermost gives organizations more control over infrastructure, deployment and data.

The main decision is therefore not about whether both platforms support channels, threads or file sharing. They do. The more important question is how much infrastructure control the organization needs and how much operational responsibility it is prepared to take on.

For teams that want a managed cloud platform and a large application ecosystem, Slack fits that model. For organizations that need self-hosting, deeper customization or deployment inside controlled infrastructure, Mattermost fits a different set of requirements.

If the requirement extends beyond messaging to self-hosted video conferencing and interoperability with existing communication infrastructure, TrueConf represents another option to evaluate.