When Slack’s Pro plan jumped to $8.75 per user per month and the 90-day message retention cap held firm on the free tier, a lot of CFOs got out their calculators. A 100-person team is now $10,500 a year just to chat - more than that company’s likely spending on its actual project management tool.

The Slack alternatives market has matured fast. Microsoft Teams is genuinely good now. Mattermost has become the default for engineering teams that want to self-host. Discord has quietly invaded the small-business segment. The question isn’t whether to leave Slack - it’s where you’d go.

Why Teams Are Leaving Slack

The price story is the headline, but it’s not the whole story. Three other complaints come up constantly. Search has gotten worse, not better, since the AI features rolled out. Notifications have grown unreliable on mobile, particularly on Android. And the 90-day message limit on free turned a flexible communication archive into a memory-loss tax.

There’s also the slow accretion of “Slack-related work” - DMs about DMs, threads about who saw what thread - that has made many teams quietly hostile to the medium itself.

The 5 Best Slack Alternatives

1. Microsoft Teams - Best for Microsoft 365 Shops

Microsoft Teams:  ★★★★☆ 4.3/5

Teams is included with Microsoft 365 Business Basic ($6 per user) and up. If you already have M365, Teams is effectively free.

Teams 2026 is a different product than Teams 2022. The new client is faster, the channels finally support proper threading, and meetings are tightly integrated with the calendar in a way Slack Huddles can’t match. For a company already on Outlook, OneDrive, and SharePoint, Teams turns chat into the connective tissue between docs, calls, and email.

Pros

  • Bundled at no extra cost with every Microsoft 365 Business and Enterprise license, saving $8-12/user vs. adding Slack separately
  • Co-author Word, Excel, and PowerPoint files in real time without leaving the Teams window via embedded SharePoint tabs
  • Meetings support up to 300 participants on free and 1,000 on Business Basic, with live captions in 30+ languages
  • Teams Phone System replaces traditional PBX with PSTN calling, call queues, and auto-attendants starting at $8/user/month add-on
  • Copilot in Teams generates meeting summaries, action items, and follow-up tasks from transcript data in real time

Cons

  • Desktop app regularly consumes 800MB-1.5GB of RAM even when idle, causing slowdowns on machines with 8GB or less
  • Notification settings are split across Activity, Chat, Channel, and per-meeting controls with no single unified preferences pane
  • Guest access for external collaborators requires Azure AD configuration and cannot share files from private channels
  • Mobile app lacks full Whiteboard, Loops, and breakout room creation available on desktop

Where Teams loses to Slack: third-party integrations are still fewer and clunkier, the bot ecosystem is thinner, and search remains a weak point. Power users will miss Slack’s keyboard shortcuts.

2. Mattermost - Best Self-Hosted Option

Mattermost:  ★★★★☆ 4.4/5

Mattermost is free for self-hosted teams (open source), $10 per user (Professional cloud), and custom for Enterprise. Self-hosted has no user cap.

For engineering organizations, Mattermost is the obvious move. The product is unapologetically Slack-shaped - same channels-and-DMs model, same slash commands, similar integrations - but you can run it on your own infrastructure. For regulated industries (defense, finance, healthcare), this is often the only viable option.

Pros

  • Self-hosted deployment keeps all messages, files, and user data on your own servers — critical for organizations bound by HIPAA, FINRA, or government data residency requirements
  • Native integrations with GitLab, Jira, Jenkins, GitHub, and PagerDuty make it a natural fit for engineering teams already using DevOps toolchains
  • Playbooks feature provides structured incident response and runbook workflows built directly into the messaging platform, replacing separate tools like PagerDuty or Opsgenie for coordination
  • Unlimited message history on the free self-hosted plan versus Slack's 90-day limit on its free tier, preserving institutional knowledge at no cost
  • Open source codebase allows custom plugins, themes, and integrations that you fully control without waiting for a vendor's feature roadmap

Cons

  • App ecosystem has roughly 300 integrations compared to Slack's 2,600+ in its App Directory, so non-developer tools like Salesforce or HubSpot may need webhook workarounds
  • Mobile apps have noticeably slower push notification delivery (2-5 second delay) and lack feature parity with desktop, especially for threaded conversations and reactions
  • Self-hosted administration requires PostgreSQL or MySQL setup, Nginx reverse proxy configuration, and ongoing maintenance that smaller teams may not have capacity for
  • No native video conferencing — you need to integrate Zoom, Jitsi, or another third-party tool for video calls, while Slack offers built-in Huddles

The trade-off is that you’re running infrastructure. Plan on a part-time SRE for any deployment over 200 users.

3. Discord - Best for Communities and Small Teams

Discord is free for almost everything. Nitro at $9.99 per user per month adds upload limits and HD streaming. There’s no business pricing.

Discord moved into work seriously over the last two years. Forum channels, threads, voice channels you can drop into without scheduling - all of these solve real workplace problems. For studios, agencies, and creator-led businesses under 50 people, Discord has become a legitimate Slack replacement at $0.

The downside: it doesn’t look like a business tool, which can be a deal-breaker for client communication. Compliance features are limited. And the gaming-native UX has rough edges (channel categories don’t behave like channels in Slack, mentions are noisier).

4. Google Chat - Best for Google Workspace Teams

Google Chat is included with Google Workspace plans starting at $6 per user. If you’re a Workspace shop, you already have it.

Google Chat 2026 is a real product, not the half-finished Hangouts replacement it was three years ago. Spaces work like Slack channels, threading is solid, and the Drive/Docs integration is unbeatable for collaborative writing. Search uses Google’s actual search infrastructure and benefits from it.

The weakness is third-party integrations and bots, which lag every alternative on this list. Google Chat is the right pick if your work centers on Google Docs and Sheets.

5. Rocket.Chat - Best Privacy-First Option

Rocket.Chat is free self-hosted, $4 per user (Starter cloud), $7 (Pro), Enterprise custom.

Rocket.Chat is what Mattermost was five years ago: a Slack alternative for the privacy-conscious. End-to-end encryption is available on every tier, federation between Rocket.Chat instances is built-in, and the deployment story is mature. It’s not as polished as Mattermost, but it’s the more open-source-pure option.

Who Should Choose Which

Choose Microsoft Teams if you’re on Microsoft 365 already. It’s the lowest-effort, lowest-cost, lowest-risk move.

Choose Mattermost if you’re an engineering-heavy team or have data residency requirements. The self-hosted option is the killer feature.

Choose Discord if you’re under 50 people, vibes-driven, and price-sensitive. Don’t pick it if you have enterprise clients who need a business-shaped vendor.

Choose Google Chat if Workspace is your stack and Docs is where work happens.

Choose Rocket.Chat if you want full data sovereignty and want a real alternative to “the SaaS option.”

Cost Reality Check (100 users, annual)

  • Slack Pro: $10,500
  • Teams (via M365 Business Basic): $7,200, but you get Office, Outlook, OneDrive too
  • Mattermost Cloud Professional: $12,000 (Self-hosted: ~$2,000 in infra)
  • Discord: $0 base, ~$2,000 if half your team takes Nitro
  • Google Chat (via Workspace Business Starter): $7,200
  • Rocket.Chat Starter Cloud: $4,800

The economics tell you most of what you need to know.

Frequently Asked Questions

Can I migrate Slack history to these tools?

Partially. Mattermost has the most mature Slack importer (channels, users, messages, file attachments). Teams imports channels and users but message history transfer is limited. Discord and Google Chat don’t have official Slack importers - you’ll be exporting Slack data for archive purposes only.

Which has the best video calling?

Teams, by a wide margin. The video stack is genuinely the best in this category, with proper noise suppression, transcription, and meeting recording on every tier. See our Slack vs Microsoft Teams comparison for a deeper look.

What about workplace etiquette - won’t switching disrupt the team?

Less than you think. Most communication tools have converged on similar patterns - channels, DMs, threads, mentions. The first week is uncomfortable; by week three, the team is faster than they were on Slack. The disruption is real but bounded.

Does any alternative integrate as well as Slack?

Honestly, no. Slack’s integration ecosystem still leads. If you have 30+ third-party Slack apps you genuinely use, Teams is the closest second, but you’ll lose some integrations.

The Verdict

For most teams leaving Slack in 2026, Microsoft Teams is the right move. The cost story is unbeatable when bundled with M365, the product has caught up dramatically, and the migration path is well-trodden. If you’re not on Microsoft and don’t want to be, Mattermost is the strongest pure alternative - especially for engineering-led organizations.

The Slack-or-nothing era is over. Start a 14-day trial of your top pick and run a single department on it. The decision will make itself.