5 Slack Alternatives In Brief That Save You Money
Teams spending €8.25+ per user per month are looking for a way out. Here are the alternatives winning right now—including why Mattermost works best on Opsily.
The Slack math doesn't add up anymore
Slack charges per seat. Ten people = €82.50/month minimum. Hundred people = €825/month. And after a year? Older messages disappear.
Meanwhile, alternative chat platforms have quietly matured. They're faster, cheaper, and some let you own your data. Teams are waking up to this.
The top choices right now: Microsoft Teams (if you're already in Office 365), Rocket.Chat (open-source, great for technical teams), Element (federated, hardcore privacy), Zulip (topic-based threading), and Mattermost (the fastest-growing open-source alternative—39.2K stars on GitHub).
Here's how they stack up.
Why Mattermost Works Better Than Slack
Key differences that matter to teams thinking about switching.
Pricing as of September 2026. Slack Pro (annual) and Mattermost on Opsily Small plan. Your team size determines actual savings.
Quick look: The 5 alternatives winning right now
Microsoft Teams
Best if: You're already paying for Microsoft 365. Cost: Often included in Microsoft bundles (€6+ user/mo). Why it wins: Tight Office integration, battle-tested at scale. Why it loses: Per-user pricing, vendor lock-in, message retention still an issue.
Rocket.Chat
Best if: Your team needs open-source without giving up features. Cost: €9/mo (managed) or free (self-hosted). Why it wins: Advanced chat, video, bots. Strong community (15K+ GitHub stars). Why it loses: Smaller ecosystem, fewer integrations than Slack.
Element (Matrix/Synapse)
Best if: Privacy and decentralization matter more than ease. Cost: €9/mo (managed) or free (self-hosted). Why it wins: Federated (decentralized), end-to-end encryption by default, portable identity. Why it loses: Steeper learning curve, smaller app ecosystem.
Zulip
Best if: Your team handles complex conversations across many projects. Cost: €10/mo (managed) or free (self-hosted). Why it wins: Topic-based threading (cleaner than Slack's threads), great for async work. Why it loses: Smaller network effect, less mainstream.
Mattermost
Best if: You want scale, compliance, and to avoid SaaS bills. Cost: €9/mo (managed on Opsily) or free (self-hosted). Why it wins: 39.2K stars. Used by Uber, Samsung, GitLab. Unlimited users and message history at one flat price. Why it loses: Slightly steeper learning curve than Slack, smaller integrations library (still 600+).
Start your whole team on Mattermost—flat rate, unlimited users.
Managed and hosted in your choice of 21 EU locations. No message deletion. No per-seat surprises. Cancel anytime.
See plan detailsWhy Opsily for Mattermost
Switching to Mattermost is one decision. Choosing where to host it is another. Here's why Opsily wins.
Flat-rate pricing. No surprises.
€30/mo for your whole team, no matter the size. Add 5 people or 500—same price. No per-user math. No module add-ons. No overage fees.
EU data. GDPR compliant.
Your data lives in German data centers with enterprise-grade security. You pick the region. We handle backups, updates, and compliance. You own your data.
Managed, not abandoned.
Daily automated backups. One-click updates. 24/7 monitoring. If something breaks, we fix it. You focus on chat, not infrastructure.
Built for teams who need reliability
Deploy Mattermost on Opsily in 3 steps
No credit card. No long contract. Start free, upgrade when you're ready.
Email and password, choose your EU region. Takes 2 minutes.
Your instance is provisioned and ready. Invite your team. Start chatting.
Backups, updates, scaling, monitoring. You manage users and integrations.
Email and password, choose your EU region. Takes 2 minutes.
Your instance is provisioned and ready. Invite your team. Start chatting.
Backups, updates, scaling, monitoring. You manage users and integrations.
Sign up
Email and password, choose your EU region. Takes 2 minutes.
Mattermost is live
Your instance is provisioned and ready. Invite your team. Start chatting.
We handle the rest
Backups, updates, scaling, monitoring. You manage users and integrations.
Pricing that scales with you
All plans include daily automated backups, GDPR-compliant hosting in your choice of EU locations, and 24/7 monitoring. Upgrade or downgrade anytime.
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Trust & Compliance
Your data is your data. Here's how we protect it.
GDPR Compliant
Your data stays under EU law. We don't sell it, trade it, or share it with ad networks.
EU Data Centers
Your Mattermost instance is hosted in German data centers with enterprise-grade security. You choose the region.
Automatic Backups
Every instance is backed up daily and encrypted at rest. Recovery available on demand.
No Message Deletion
Unlike Slack's 90-day limit, all your message history stays. Configurable retention per channel.
Frequently Asked Questions
Everything you need to know about switching to Mattermost on Opsily.
Mattermost provides mmetl, a migration tool that exports every message, file, thread, reaction, and user from Slack. The import is lossless and includes full search indexing. The time required depends on data volume: 2-4 hours per 10K messages. Integrations (GitHub, Jira, Zapier, etc.) carry over via webhooks. Slack apps built with Workflow Builder require manual rebuild on Mattermost, but most teams find Mattermost's native automation (playbooks, bots) more powerful. Opsily provides migration support to walk you through the cutover.
Stop paying per seat. Start using Mattermost.
Opsily's managed Mattermost is ready to deploy. No credit card, no lock-in contract, cancel anytime.