The Best Slack Alternatives in 2026 (Free & Open-Source)
Tolodora Editorial Team
Tolodora's editorial team — we research, compile and regularly update these software guides from public sources and product documentation.
Quick answer
The best Slack alternatives in 2026 are Microsoft Teams, Discord and Mattermost. Microsoft Teams is our top overall pick, best for businesses already using Microsoft 365 that want chat plus meetings. See the full ranked comparison below.
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Slack popularized channel-based team chat, but its per-user pricing and the free plan's limits (like restricted message history) send many teams searching for alternatives. Whether you want an all-in-one suite, a free option, or open-source software you can self-host, there's a strong fit.
These all offer real-time team messaging with channels, DMs, and integrations — they differ on price, video/meetings, and whether you can self-host.
We rated every pick on four things — pricing and value, functionality, ease of use, and support. Here's the rundown.
| Tool | Value | Support | Ease of use | Features | Overall | Best for |
|---|---|---|---|---|---|---|
| Pumble | 9.8 | 8.4 | 9.0 | 8.2 | 8.8 | Budget teams that want free, unlimited team chat. |
| Mattermost | 9.2 | 8.4 | 8.0 | 9.0 | 8.7 | Technical and security-conscious teams that want to self-host. |
| Microsoft Teams | 8.0 | 8.6 | 8.2 | 9.2 | 8.5 | Businesses already using Microsoft 365 that want chat plus meetings. |
| Rocket.Chat | 9.2 | 8.2 | 7.8 | 8.8 | 8.5 | Organizations wanting open-source chat plus customer messaging. |
| Discord | 9.4 | 7.6 | 8.4 | 8.4 | 8.4 | Communities and startups that want free, lively real-time chat. |
| Google Chat | 8.8 | 8.2 | 8.6 | 8.2 | 8.4 | Teams already on Google Workspace. |
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| # | Tool | Best for | Rating |
|---|---|---|---|
| 1 | Microsoft Teams | Businesses already using Microsoft 365 that want chat plus meetings. | 4.3/5 |
| 2 | Discord | Communities and startups that want free, lively real-time chat. | 4.2/5 |
| 3 | Mattermost | Technical and security-conscious teams that want to self-host. | 4.3/5 |
| 4 | Google Chat | Teams already on Google Workspace. | 4.2/5 |
| 5 | Rocket.Chat | Organizations wanting open-source chat plus customer messaging. | 4.3/5 |
| 6 | Pumble | Budget teams that want free, unlimited team chat. | 4.4/5 |
Microsoft Teams
- Pricing
- 8.0/10
- Functionality
- 9.2/10
- Ease of use
- 8.2/10
- Support
- 8.6/10
What I like
Chat, video meetings, and deep Microsoft 365 integration in one suite, with a solid free tier.
Best for
Businesses already using Microsoft 365 that want chat plus meetings.
If you run this kind of your busines operation, it belongs on your list. Teams bundles messaging, video calls, and file collaboration tightly with Office apps, making it the natural all-in-one Slack alternative for Microsoft shops.
Discord
- Pricing
- 9.4/10
- Functionality
- 8.4/10
- Ease of use
- 8.4/10
- Support
- 7.6/10
What I like
Free, fast real-time chat with voice channels, roles, and a huge bot ecosystem.
Best for
Communities and startups that want free, lively real-time chat.
Discord offers free text and voice channels with rich integrations; increasingly used by companies and communities as a no-cost Slack alternative. For your business, it's one of the stronger options on this shortlist.
Mattermost
- Pricing
- 9.2/10
- Functionality
- 9.0/10
- Ease of use
- 8.0/10
- Support
- 8.4/10
What I like
Open-source, self-hostable team chat with strong security and compliance controls.
Best for
Technical and security-conscious teams that want to self-host.
Plenty of your business land on it after weighing the field. Mattermost is the leading open-source Slack alternative: self-host it for full data ownership, with channels, integrations, and enterprise-grade security.
Google Chat
- Pricing
- 8.8/10
- Functionality
- 8.2/10
- Ease of use
- 8.6/10
- Support
- 8.2/10
What I like
Included with Google Workspace, integrated with Gmail, Docs, and Meet.
Best for
Teams already on Google Workspace.
It tends to suit your business that want exactly this balance. Google Chat provides spaces and direct messages woven into Gmail and the Google suite, a convenient built-in Slack alternative for Workspace users.
Rocket.Chat
- Pricing
- 9.2/10
- Functionality
- 8.8/10
- Ease of use
- 7.8/10
- Support
- 8.2/10
What I like
Open-source, highly customizable chat with omnichannel and self-hosting.
Best for
Organizations wanting open-source chat plus customer messaging.
That focus makes it a natural fit for many your business. Rocket.Chat is an open-source, self-hostable platform that adds omnichannel customer communication on top of team chat, great for control and flexibility.
Pumble
- Pricing
- 9.8/10
- Functionality
- 8.2/10
- Ease of use
- 9.0/10
- Support
- 8.4/10
What I like
Free team chat with unlimited users and message history, from CAKE.com (Clockify, Plaky).
Best for
Budget teams that want free, unlimited team chat.
It tends to suit your business that want exactly this balance. Pumble, part of the CAKE.com suite, offers free team messaging with unlimited users and searchable history — a standout value Slack alternative that pairs with Clockify and Plaky.
The verdict
Want an all-in-one with video and Office? Microsoft Teams. Free real-time community-style chat? Discord. Open-source and self-hosted? Mattermost or Rocket.Chat. Already on Google Workspace? Google Chat.
Frequently asked questions
What is the best free Slack alternative?
Discord and Google Chat are free (Google Chat with a Google account), and Mattermost and Rocket.Chat are free to self-host. Microsoft Teams also has a capable free tier.
Is there an open-source Slack alternative?
Yes — Mattermost and Rocket.Chat are both open-source and self-hostable, giving you full control of your data with no per-user cloud fees.
What is the best Slack alternative for large teams?
Microsoft Teams scales well for enterprises (especially with Microsoft 365), while Mattermost is favored by large technical teams that want self-hosting and security.
Which alternative keeps unlimited message history for free?
Self-hosted options like Mattermost and Rocket.Chat keep your full history at no per-message cost, unlike Slack's free plan which limits history.
Can I replace Slack completely?
For most teams, yes — Teams, Discord, or a self-hosted Mattermost/Rocket.Chat cover channels, DMs, calls, and integrations. The right pick depends on whether you prioritize an all-in-one suite, cost, or self-hosting.
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