Slack set the standard for team chat, but two things send teams looking elsewhere: the free plan now hides messages older than 90 days, and paid seats add up fast as you grow. There is also no self-hosting, so regulated and security-conscious organizations cannot keep their data in-house. Beyond cost, plenty of teams simply find the always-on channel model noisy and want either tighter async threading or full control of their stack. The alternatives below fall into three camps: free community-style chat, the Microsoft 365 bundle, and open-source platforms you can self-host. Which one fits depends on whether your priority is price, ecosystem, or data ownership.
Who should switch from Slack
- You keep losing history to the 90-day free limit - open-source Mattermost or Rocket.Chat retain everything on infrastructure you control.
- You are already paying for Microsoft 365 - Teams is effectively bundled, so you are double-paying for chat with Slack.
- You have compliance or data-residency requirements - self-hosted Mattermost, Rocket.Chat, or Zulip keep messages inside your own network.
Slack alternatives compared
| Tool | Best for | Free plan | Starting price | Open source | Key differentiator |
|---|---|---|---|---|---|
| Discord | Communities and voice | Yes | Free | No | Free, persistent voice channels and a community model Slack cannot match. |
| Microsoft Teams | Existing Microsoft 365 shops | Yes | Free | No | Chat, meetings, and Office files unified - and effectively free if you already pay for M365. |
| Mattermost | Self-hosted, regulated teams | Yes | Free | Yes | Open-source, self-hostable Slack alternative with full data ownership. |
| Rocket.Chat | Self-hosted omnichannel chat | Yes | Free | Yes | Open-source platform that combines internal team chat with customer-facing channels. |
| Zulip | Async, topic-based teams | Yes | Free | Yes | Topic-based threading that keeps async conversations organized instead of a single scrolling channel. |
Mattermost, Rocket.Chat, and Zulip are open source and free to run yourself. A small team can self-host on a $5/month VPS - roughly $60/year total - versus Slack's paid seats at about $7-12.50/user/month, which for a 20-person team runs into thousands per year. The trade is operational ownership for that saving.
Discord — Best Slack Alternative for Communities and Always-On Voice
Discord offers unlimited message history and drop-in voice channels for free, which is why communities and many startups adopt it. Voice, screen-share, and large-group chat are first-class rather than upsells.
Pricing: Free, with optional Nitro perks for individuals. No per-seat business pricing.
Best for: Communities, open-source projects, and informal teams that value free voice and unlimited history.
The catch: It lacks business compliance, admin controls, and the threaded, work-oriented structure of Slack.
Microsoft Teams — Best Slack Alternative for Microsoft 365 Organizations
Teams bundles chat with video meetings and deep Office integration, so documents, calls, and conversations live together. For organizations already on Microsoft 365, it removes a separate chat bill entirely.
Pricing: Free standalone tier; included with Microsoft 365 business plans starting around $4/user/month.
Best for: Enterprises and SMBs standardized on Microsoft 365 and Office.
The catch: The interface is heavier and less polished than Slack, and it shines mainly inside the Microsoft ecosystem.
Mattermost — Best Slack Alternative for Self-Hosted, Compliance-Heavy Teams
Mattermost looks and feels like Slack but runs on your own servers, so messages, files, and compliance stay under your control. It is popular with government, defense, and engineering teams that cannot use a public SaaS.
Pricing: Free and open source to self-host; paid tiers add enterprise features. Your main cost is the server it runs on.
Best for: Security- and compliance-driven organizations that need data residency and on-prem control.
The catch: You own the operations - hosting, upgrades, and backups - and the integration catalog is smaller than Slack's.
Rocket.Chat — Best Slack Alternative for Open-Source Team and Customer Messaging
Rocket.Chat is a self-hostable communications hub: internal channels plus omnichannel customer messaging (livechat, WhatsApp, email) in one open-source platform. You control hosting, branding, and data.
Pricing: Free and open source to self-host; paid cloud and enterprise tiers available.
Best for: Teams that want both internal chat and customer conversations on infrastructure they own.
The catch: Self-hosting carries setup and maintenance overhead, and the experience is less refined than Slack.
Zulip — Best Slack Alternative for Threaded, Async Discussions
Zulip's model splits every channel into named topics, so parallel conversations stay separate and catching up after time away is fast. It is open source, free to self-host, and built for distributed, async teams.
Pricing: Free and open source to self-host; a free cloud tier and paid plans are also available.
Best for: Remote and open-source teams that prefer structured, asynchronous discussion over real-time noise.
The catch: The topic model takes adjustment, and the interface is more utilitarian than Slack's.
How to choose your Slack alternative
- Do you need to own and retain your data? If compliance or history matters, choose a self-hostable open-source option.
- Are you already paying for Microsoft 365? If so, Teams removes a duplicate chat bill.
- Is your team real-time or async-first? Real-time, voice-heavy groups suit Discord; structured async teams suit Zulip's topic threading.
Frequently asked questions
Discord is free with unlimited history and voice for informal teams and communities. For business use with data ownership, Mattermost, Rocket.Chat, and Zulip are free and open source to self-host.
Yes - Mattermost, Rocket.Chat, and Zulip are all open source and can run on your own servers, keeping messages and files inside your infrastructure for compliance and data residency.
Discord and Teams' free tiers cost nothing, and self-hosted Mattermost or Zulip can run for the price of a small server (about $60/year) instead of Slack's per-seat fees of roughly $7-12.50/user/month.
On the free plan, messages older than 90 days become inaccessible. Paid plans keep full history. Open-source alternatives you self-host retain everything with no time limit.
Teams wins on value if you already use Microsoft 365 and on built-in meetings. Slack wins on polish, app integrations, and developer ecosystem. The deciding factor is usually which suite you already pay for.
About Slack
Channel-based messaging for work