Mattermost and Slack are two of the biggest names in team communication and, at first glance, they seem pretty similar.
I tested both apps hands-on to figure out which one actually works better for day-to-day use.
Here’s what I found.
Table of Contents
Mattermost vs Slack: Main features comparison
The main differences between Mattermost and Slack are:
- Customization options,
- Integration, and
- Storage options.
While Mattermost gives you unlimited storage through self-hosting (limited only by your server capacity), Slack stands out with more customization options and a larger number of integrations.
In the table below, you can see and compare the features of both Mattermost and Slack.
| Features | Mattermost | Slack |
|---|---|---|
| Pricing plans | – Free self-hosting Team Edition / Free tier of the Enterprise Edition without a license – Professional: $10 per user per month, billed annually – Enterprise & Enterprise Advanced — quote upon request | – Free (90 days worth of message history and file storage) – Pro: $8.75 per user per month, billed monthly – Business+: $18 per user per month, billed monthly – Enterprise+ — quote upon request |
| Interface | Clean, advanced customization | Clean, customizable, easy to navigate |
| Communication options | – Channels for group conversations – Playbooks for managing recurring processes – Boards (with an additional plugin) for task tracking | – Channels for group conversations – Canvases for notes, agendas, or shared docs – Huddles for audio/video calls |
| Notifications | – Customized notifications – DND | – Customized notifications – DND |
| Search options | Advanced | Advanced |
| File sharing and storage options | Unlimited storage in the self-hosting plans (as much space as you have on your server) | – Free: 5 GB file storage for a team for 90 days – Pro: 10 GB per user – Business+: 20 GB per user – Enterprise: 1 TB per user |
| Integrations | 700+ integrations, no limit in self-hosting plans | 10 integrations limit in free plan, 2600+ integrations in paid plans |
| Support | – FAQs / Community Forum – Knowledge Base / Help Center – Customer success teams and 24/7 support in paid plans | – FAQs / Community Forum – Knowledge Base / Help Center – Customer success teams and 24/7 support in paid plans |
| Security | – Standard security – Self-hosting | – Standard security – No self-hosting |
We briefly got you acquainted with the main features of both apps, and now it’s time to dive into a more detailed comparison.
Mattermost vs Slack: Mattermost is pricier, but less limiting
In the first round, we’ll cover pricing plans.
Right now, the only free way to use Mattermost is by self-hosting the open-source version, known as Mattermost Team Edition, or the free tier of the Enterprise Edition without a license, both recommended for teams under 50 members.
By default, installing Mattermost gives you the Enterprise Edition, which includes the free Team features and an optional 30-day trial of the paid Enterprise features.
I used the free self-hosted version, and I’ll be honest — setting it up was extremely complicated and technical. It took a lot of help from more tech-savvy people to get it running.
But if you make it past the setup, here’s what the free version includes:
- Multiple workspaces,
- Unlimited users, channels, playbooks, and boards,
- No storage limitations because it’s self-hosted (you need to manage the storage space on your server, i.e., make sure you have enough disk space for everything Mattermost stores),
- 1:1 audio calls with optional screen sharing, and
- Access to unlimited message history (depending on the available storage space on your server).
Aside from the free plan, Mattermost has 3 paid plans — Professional, Enterprise, and Enterprise Advanced.
The Professional plan costs $10 per user/month, billed annually, and it includes:
- Unlimited workspaces,
- Group calls with screen sharing,
- Unlimited message search and history (up to 3 million posts),
- Guest accounts, and
- Custom user groups.
If you need a more secure solution, with advanced features and compliance, check out their Enterprise or Enterprise Advanced plans.
Slack’s free plan offers 5 GB of storage for the entire workspace and access to the most recent 90 days of message history.
It also only allows for 1:1 meetings and 1:1 external messages. All of which is quite limiting.
Upgrading to Slack’s first paid plan brings significant benefits, such as:
- Unlimited message history,
- Unlimited app integrations,
- 10 GB of file storage per user,
- Group meetings,
- Group external messages, and more.
The paid plans of both apps come with trade-offs.
Slack’s Pro plan is a bit cheaper and far easier to set up, but the 10 GB storage limit per user feels restrictive for the price.
Mattermost Professional costs a bit more and the self-hosting setup is a hassle. But if message history and storage are your priorities, it may still be worth the extra effort.
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Mattermost vs Slack: Both have clean designs, but Slack is easier to navigate
If you, like most of us, spend a good portion of the day looking at your messaging app, it helps if the interface is not just intuitive and user-friendly, but also easy on the eyes.
When comparing Mattermost and Slack, I quickly noticed that both have clean, modern interfaces. But when it comes to customization and language support, there are a few differences worth pointing out.
Mattermost offers a wide range of options, including:
- Support for 16 languages,
- A variety of display customizations, and
- Premade and custom themes.
Slack, on the other hand, offers:
- Support for 12 languages,
- Sidebar customization,
- Theme options: light/dark modes, built-in themes, and fully custom themes, and
- Emoji customization.
While both platforms offer similar customization features, Mattermost supports a few more languages.
That said, I personally prefer Slack’s interface — everything is laid out clearly, and I find it easier to navigate overall.
Mattermost vs Slack: Mattermost offers more features for team communication and collaboration
Both Mattermost and Slack offer group messaging in public and private channels, along with direct messages for 1-on-1 communication. But there are a few extra features that set them apart.
Mattermost’s free self-hosted version includes:
- 1:1 audio calls with optional screen sharing,
- Playbooks, and
- Boards (may require enabling a plugin).
Playbooks are customizable checklists designed to help teams stay on top of recurring tasks and responsibilities. They’re especially handy for keeping everyone aligned and making sure deadlines aren’t missed.
After going through the (honestly exhausting) self-hosting setup of Mattermost, I wasn’t too eager to mess with plugins just to try out the Boards. Enabling extra features like that felt like another technical hurdle, and after spending hours getting it to work in the first place (and recovering it after a mysterious crash), I decided not to risk breaking anything.
Slack’s free version also covers the basics:
- Channels,
- Direct messages,
- 1:1 meetings,
- 1:1 external messages, and
- Canvases (within channels and DMs only — standalone canvases require a paid plan).
Slack Canvases are collaborative documents designed to help teams share important information, document processes, and keep everyone on the same page. They’re useful for organizing notes, collecting resources, or summarizing key decisions all in one place, right where your conversations happen.
Both apps support threaded conversations, which makes it easier to follow specific topics without cluttering the main chat feed.
If you’re looking for a tool that supports asynchronous communication, either app will serve you well.
That said, one major difference is in how they handle message history. Slack’s free plan limits access to messages from the last 90 days — which, in my opinion, feels like a very short window. Mattermost’s free self-hosted version, on the other hand, allows unlimited message history, as long as you manage your own storage.
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Mattermost vs Slack: Slack offers more notification customization
Let’s face it: no one likes distractions while doing some deep work.
On the other hand, you also don’t want to miss important messages from your colleagues.
So, what should you do?
The best way to stay in the loop with your colleagues, but also not get overwhelmed by notifications, is to configure them according to your wishes.
Luckily, both Mattermost and Slack offer options for customizing your notifications.
Let’s start with Mattermost.
This communication and collaboration tool notifies you of messages directed at you, as well as when someone:
- Mentions you,
- Notifies a channel you’re a member of using @channel or @all, and
- Uses keywords you configured.
Just like Mattermost, Slack notifies you when:
- Someone sends you a direct message,
- Someone mentions you or uses your configured keywords,
- You receive a message from Slackbot, or
- Someone replies to a thread you’re following.
Another useful feature that both Mattermost and Slack offer is setting Do Not Disturb (DND) mode. For teams that work across time zones, this is especially useful.
However, since Slack offers more customization options, it is the winner for me in this category.
Mattermost vs Slack: Both apps offer advanced search options
Search for information or files can be a major time sink if the communication tool you’re using doesn’t have adequate search capabilities.
Apart from losing time, you might lose your nerves — and all of that might affect your productivity.
Thanks to their advanced search options, both Mattermost and Slack help you avoid these inconveniences, as well as information overload.
In Mattermost, you can search messages, replies, and file names. File content may also be searchable, depending on your server setup.
Your searching is made easier with the help of manual search modifiers, including:
- Exclusion symbol (-) to leave out specific words,
- Quotation marks for exact phrase searches,
- Hashtags to find tagged messages, and
- Filters for user, channel, or date-based searches.
Slack also allows you to easily find anything you’re looking for, be it:
- Messages,
- Files,
- People,
- Channels, or
- Canvases.
Just like Mattermost, Slack lets you search within a specific period and exclude channels from your search.
Both apps have all the search modifiers you might need to streamline your workflow. That being said, I personally found Slack’s search a bit easier to navigate, mainly because the filters are cleanly laid out and easy to customize.
Mattermost vs Slack: Mattermost offers more space, Slack has larger file limits
Efficient file sharing is vital for good collaboration.
For example, during virtual meetings, it’s really important to me that sharing reports or documents is quick and easy in the team communication app we’re using. It saves time and keeps the conversation flowing.
So, let’s see what Mattermost and Slack have in terms of file sharing and storage, starting from Mattermost.
Mattermost allows sharing of up to 10 files per post, with the default maximum file size being 100 MB. However, system administrators can change this limit, via the configuration settings.
At the same time, Slack enables you to share files of up to 1 GB in size for all plans.
Moving on to storage — this is where things take a turn.
Namely, Mattermost offers unlimited storage in the free self-hosting plan, as much space as you have on your server. Slack only gives you 5 GB of free storage, and even the cheapest paid plan bumps that up to just 10 GB per team member.
For me, that feels pretty limiting, especially considering Slack’s price tag.
So, if self-hosting is your preference and you can manage it for your team, storage is a handy benefit that comes with it.
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Mattermost vs Slack: Slack’s free plan is limited, but paid plans offer way more integrations
I find that good third-party integrations are essential for improving remote work and keeping my workflow smooth.
Mattermost supports over 700 integrations through plugins, extensions, and bots.
Since the free version is self-hosted, there’s no built-in limit on integrations — the number you can use depends on your server’s capacity and resources.
Now, let’s look at Slack.
On its free plan, Slack allows up to 10 app integrations. However, Slack’s paid plans offer access to over 2,600 integrations.
So, while Slack’s free tier is quite limited, its vast integration ecosystem makes it a strong choice if having many app connections is important to your team.
Mattermost vs Slack: Paid plans offer similar support
Personally, having reliable and responsive support is really important to me, especially when setting up features I’m not familiar with. If something goes wrong, I don’t want to waste hours digging through forums trying to fix it.
In their free plans, both Mattermost and Slack offer exactly that — basic support through self-service resources, including:
- FAQs / Community Forum
- Knowledge Base / Help Center
Since I went through the whole self-hosting setup, I have more first-hand experience with Mattermost’s support. I used their chatbot a couple of times to clear up questions, but honestly, their documentation wasn’t the easiest to follow. I wish there were simpler explanations, especially for people who aren’t developers or super technical. That’s why I ended up calling in friends for help instead of relying solely on Mattermost’s guides.
When it comes to support in paid plans, Mattermost offers:
- Professional plan: Business hours support, and
- Enterprise plan: Guaranteed support 24/7, with a 4-hour response time.
Both paid plans offer additional support as add-ons.
Moving on to Slack, as you upgrade, you get:
- Pro plan: 24/7 support,
- Business+ plan: 24/7 support with a 4‑hour first‑response time, and
- Enterprise+ plan: 24/7 priority support with a 4‑hour first‑response time.
Both apps offer good support on paid plans, so there’s not much to set them apart here. But when it comes to the free plans, there’s still a lot left to be desired.
Pumble gives you 24/7 support — even on the free plan!
Mattermost vs Slack: Self-hosting gives Mattermost a security edge
The last category in our showdown is security, an essential feature for your data protection.
When choosing a communication tool, high security should be non-negotiable. That’s why it helps if an independent body has verified privacy, security, and compliance of the tool you’re using.
Both Mattermost and Slack support encryption-in-transit and encryption-at-rest.
Starting with Mattermost, they boast regular security updates and are compliant with:
- HIPAA,
- FINRA,
- SOC 2 Type I,
- GDPR, and
- CCPA.
Aside from that, Mattermost’s self-hosted solution is the best way to be in control of your data and privacy.
On the other hand, Slack is also audited against compliance and assurance programs, such as:
- SOC2,
- SOC3,
- ISO/IEC,
- APEC, and
- CSA.
Both apps offer multi-factor authentication.
However, thanks to its self-hosted option, Mattermost stands out as a more secure communication and collaboration tool.
Mattermost vs Slack: What’s the best pick for your team?
After testing and comparing Slack and Mattermost across all key categories, here’s my takeaway.
Both get the job done, but they serve slightly different needs.
Mattermost might be a better fit if you:
- Prefer hosting your own data for more control and security,
- Need unlimited message history and storage (with self-hosting), and
- Want additional tools like Playbooks and Boards.
Slack could work better if you:
- Want an easy-to-set-up solution,
- Need more integrations and customization options, and
- Prefer an interface that’s simple to navigate from day one.
To sum up, choose Mattermost if your priority is control and security. Choose Slack if your team wants something quick to adopt with plenty of apps to plug in.
Of course, these are definitely not your only two options.
Looking for a better option than Mattermost or Slack? Try Pumble
If you realize that neither Mattermost nor Slack fit your communication needs, try Pumble. It’s a team communication and collaboration app that combines:
- Ease of use,
- Powerful features, and
- Affordable plans designed to keep your team connected and productive.
While Mattermost and Slack each have their strengths, Pumble offers a simpler, more balanced solution for your team.
Unlike Mattermost, which is complicated to set up, Pumble is easy to get started with and works smoothly right away.
And unlike Slack, which limits storage and message history on its free plan, Pumble gives you unlimited message history and more generous storage, even without paying.
Pumble gives you everything you need to stay connected, including:
- Direct and group messaging,
- Channels and threaded conversations,
- Guest access,
- File sharing and screen sharing,
- Video and voice calls,
- Meeting recording,
- Video and voice messages, and more!
Plus, it’s easy to use and intuitive — no clutter, no steep learning curve, just the features your team actually needs.
Pumble by CAKE.com is built for teams who want a reliable, straightforward tool that’s a better alternative to Mattermost and Slack.
