Slack Discord Alternative: Open-Source Team Chat with Full Data Control
Tired of Slack's per-user fees and 90-day message limits? Frustrated with Discord's lack of business features? Mattermost is the self-hosted alternative teams choose for security, cost savings, and EU data residency. Deploy on Opsily's managed infrastructure in 3 minutes.
Mattermost: The Best Slack Discord Alternative vs. Competition
How the top alternatives stack up on what matters for business teams.
Pricing as of September 2026. Slack and Discord pricing subject to change. Mattermost hosting on Opsily includes all features.
Why Choose Opsily for Mattermost?
The best Slack Discord alternative for teams that demand data control. Managed hosting that protects your business.
The Best Slack Discord Alternative: No Per-Seat Pricing
Slack charges €8.25–18 per user per month. A 50-person team pays €412–900 monthly. Opsily's Mattermost hosting is €30 flat, unlimited users. Scale your team without watching the SaaS bill grow. That one decision saves mid-size teams €2,470–10,800 per year.
Your Data Stays in Europe
GDPR compliance is not a nice-to-have. Opsily runs Mattermost on servers in Germany, Netherlands, Finland, Sweden, and the UK. No US cloud. No data residency negotiation. No vendor lock-in to Slack's US infrastructure. Customers in regulated industries (finance, healthcare, government) choose this.
Full Control, Zero Maintenance
Self-hosting sounds scary. It isn't. Opsily handles backups, SSL certificates, security updates, and monitoring. You get the control of self-hosted Mattermost (data ownership, compliance, integrations) without the ops headache. Deploy in 3 minutes, no DevOps needed.
Built for teams who need reliability
Why Discord Isn't Enough (And Why Slack is Expensive)
Discord was built for gaming communities. It's free, fun, and great for casual chat. But it's not a business tool. There's no admin panel for compliance. No audit logs for regulated industries. No way to enforce retention policies or export data for legal discovery. If your team has Discord for early-stage chaos and then needs to grow up, Mattermost is the answer.
Slack is a business tool. That's its job. But the cost model punishes growth. At 5 people, €8.25/user/month feels reasonable. At 50 people, it's €412 monthly. At 100 people, you're paying €825 monthly (€9,900 yearly) just to chat. The 90-day message history limit on the Free tier forces you to upgrade or lose institutional knowledge.
Mattermost fixes both problems.
It's designed for businesses and open-source communities at scale. The Uber engineering team runs 70,000 concurrent connections on Mattermost. The U.S. Department of Defense uses it for classified messaging (SCIF-ready). Samsung, Wargaming, and GitLab run it internally. These aren't small teams trying Mattermost on the cheap — they're enterprises that chose self-hosted control over vendor lock-in.
With Opsily, you get the same Mattermost that DoD trusts, running on EU infrastructure you control, priced flat at €30/month. No per-seat pricing. No 90-day message walls. No vendor lock-in.
Get Started on Opsily in 3 Steps
From signup to live team chat.
Email + password. No credit card required. Takes 2 minutes.
Choose your EU datacenter (Germany, Netherlands, Sweden, Finland, or UK). Opsily provisions the infrastructure. Your Mattermost instance is live in 60 seconds.
Bulk-import users from Slack or Discord. Use Mattermost's API to migrate message history. Opsily's team provides migration guides if you need it. Most teams complete migration in 1 day.
Email + password. No credit card required. Takes 2 minutes.
Choose your EU datacenter (Germany, Netherlands, Sweden, Finland, or UK). Opsily provisions the infrastructure. Your Mattermost instance is live in 60 seconds.
Bulk-import users from Slack or Discord. Use Mattermost's API to migrate message history. Opsily's team provides migration guides if you need it. Most teams complete migration in 1 day.
Create Your Opsily Account
Email + password. No credit card required. Takes 2 minutes.
Deploy Mattermost with One Click
Choose your EU datacenter (Germany, Netherlands, Sweden, Finland, or UK). Opsily provisions the infrastructure. Your Mattermost instance is live in 60 seconds.
Invite Your Team and Migrate Data
Bulk-import users from Slack or Discord. Use Mattermost's API to migrate message history. Opsily's team provides migration guides if you need it. Most teams complete migration in 1 day.
Built for Trust and Compliance
Enterprise-grade security without the enterprise price tag.
GDPR Compliant
Data stored in EU datacenters only. Full compliance with GDPR data retention, portability, and deletion rights. Audit logs and compliance exports included.
EU Data Residency
Choose your datacenter: Germany, Netherlands, Sweden, Finland, or UK. No US cloud. No data transfer outside EU. Hosted on Opsily's infrastructure, not a third party.
End-to-End Encryption
Direct messages support E2E encryption. All data in transit uses TLS 1.3. Nightly encrypted backups stored separately from the main database.
Security Monitoring 24/7
Opsily monitors uptime, threats, and performance around the clock. Automatic security updates applied within 24 hours of release. Brute-force protection and rate limiting enabled by default.
SOC 2 & ISO 27001 Path
Mattermost supports the controls needed for SOC 2 Type II and ISO 27001 compliance. Comprehensive audit logs, role-based access control, and MFA for all admin users.
Transparent Pricing, No Surprises
All Mattermost features, hosted on Opsily's EU infrastructure. Unlimited team members. Choose the resources that fit your team size. Scale anytime.
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Frequently Asked Questions
Mattermost combines the best of both worlds. Like Slack, it's built for team collaboration with channels, threads, integrations, and compliance tools. Like Discord, it's cost-effective and community-driven. Unlike both, Mattermost lets you own your data: deploy it on-prem, on your private cloud, or on Opsily's EU servers. No per-seat pricing, no vendor lock-in, no 90-day message limits. Teams that have switched report saving 50-70% on messaging platform costs while gaining full data control.
Move from Slack and Discord. Keep Your Data.
Join Uber, Samsung, and the U.S. Department of Defense. Get your Mattermost instance on Opsily's EU infrastructure. Free 14-day trial, no credit card required.