We Calculated How Much Slack Actually Costs—Then Found Two Alternatives That Save Teams $15,000/Year
We Calculated How Much Slack Actually Costs—Then Found Two Alternatives That Save Teams $15,000/Year
Your CFO just sent that email again. "Can we talk about our software costs?"
You know what's coming. Slack is eating 15% of your SaaS budget, and it's growing faster than your headcount. At $15/user/month for Pro, a 50-person team burns $9,000/year on chat. Enterprise Grid? Don't even look.
Here's the thing nobody talks about: you're paying premium prices for a solved problem. Team chat isn't rocket science. And in 2025, self-hosted alternatives don't just match Slack—they beat it.
We tested Zulip, Mattermost, and Slack head-to-head. The results might make you cancel a subscription today.
The Real Cost of Slack (It's Worse Than You Think)
Let's do the math that Slack's pricing page hides:
| Team Size | Slack Pro | Slack Business+ | Slack Enterprise |
|---|---|---|---|
| 20 users | $3,600/yr | $6,000/yr | "Contact Sales" |
| 50 users | $9,000/yr | $15,000/yr | ~$25,000/yr |
| 100 users | $18,000/yr | $30,000/yr | ~$50,000/yr |
| 200 users | $36,000/yr | $60,000/yr | ~$100,000/yr |
And that's before you hit the hidden costs:
- Data exports require Enterprise (minimum ~$20/user)
- SAML SSO locked behind Business+ ($12.50/user)
- Compliance exports for regulated industries? Enterprise only
- Guest accounts count as full users
A 100-person company in healthcare or finance can easily spend $50,000+ per year just to chat.
The Self-Hosted Alternatives: Mattermost vs Zulip
Both are open-source. Both are production-ready. Both can replace Slack tomorrow. But they're built for different teams.
Mattermost: The Enterprise Slack Killer
Mattermost looks and feels like Slack. If your team uses Slack today, they'll adapt in hours, not weeks.
What it does better than Slack:
- Unlimited message history (Slack free cuts off at 90 days)
- Self-hosted = your data never leaves your servers
- DevOps integrations built-in (Jira, GitHub, GitLab, Jenkins)
- Incident management and playbooks included
- Custom branding for client-facing channels
Best for: Teams migrating from Slack who want minimal friction. DevOps and engineering teams. Companies with compliance requirements.
Deploy Mattermost in 5 minutes: Get started on Elestio — fully managed, from $26/month (4 CPU / 8GB recommended for teams).
Zulip: The Threading Champion
Zulip takes a different approach. Instead of chaotic channel scrolling, every message belongs to a topic within a stream. Think email threads, but real-time.
What it does better than Slack:
- Threading that actually works (no more "thread or channel?" confusion)
- Catch up on missed conversations without FOMO scrolling
- Open-source with no "open core" feature gating
- Lightweight—runs on minimal resources
- Keyboard-first design for power users
Best for: Remote-first teams across timezones. Open-source communities. Teams drowning in Slack notification chaos.
Deploy Zulip in 5 minutes: Get started on Elestio — fully managed, from $14/month (2 CPU / 4GB).
Head-to-Head: The Comparison Table
| Feature | Slack Pro | Mattermost | Zulip |
|---|---|---|---|
| Price (50 users) | $9,000/yr | ~$312/yr | ~$168/yr |
| Message History | Unlimited | Unlimited | Unlimited |
| SSO/SAML | $12.50+/user | ✅ Included | ✅ Included |
| Data Ownership | ❌ Slack's servers | ✅ Your servers | ✅ Your servers |
| Compliance Export | Enterprise only | ✅ Included | ✅ Included |
| Guest Accounts | Paid | ✅ Free | ✅ Free |
| Threading | Basic | Slack-style | Superior |
| Mobile Apps | ✅ Excellent | ✅ Good | ✅ Good |
| Video Calls | ✅ Huddles | Plugin needed | Plugin needed |
| Custom Integrations | App Directory | ✅ Webhooks/API | ✅ Webhooks/API |
The Savings Are Absurd
Let's be specific. A 50-person team switching from Slack Pro to self-hosted:
| Slack Pro | Mattermost (Elestio) | Zulip (Elestio) | |
|---|---|---|---|
| Year 1 | $9,000 | $312 | $168 |
| Year 2 | $18,000 | $624 | $336 |
| Year 3 | $27,000 | $936 | $504 |
| 3-Year Total | $27,000 | $936 | $504 |
| You Save | — | $26,064 | $26,496 |
That's not a typo. Over $26,000 saved in 3 years. For a 100-person team, double it.
"But Self-Hosting Is Hard"
It was. In 2015.
In 2025, platforms like Elestio handle everything:
- One-click deployment (literally 5 minutes)
- Automatic SSL certificates
- Daily backups
- Security updates applied automatically
- 24/7 monitoring
You get the cost savings and data ownership of self-hosting without hiring a DevOps engineer. Starting at $14/month for smaller instances, it covers infrastructure AND management.
Which One Should You Pick?
Choose Mattermost if:
- Your team currently uses Slack and wants familiar UI
- You need deep DevOps/CI-CD integrations
- Enterprise features (compliance, audit logs) matter
- You want the safest migration path
→ Deploy Mattermost on Elestio
Choose Zulip if:
- Your team is remote-first across multiple timezones
- You're drowning in Slack notification chaos
- Threading and async communication are priorities
- You want the most cost-effective option
Stay with Slack if:
- Money is no object
- You're locked into Salesforce/Enterprise integrations
- Change management is impossible at your org
The Bottom Line
Slack built a great product and then priced it like enterprise software. For most teams, that math stopped making sense years ago.
Mattermost and Zulip aren't compromises—they're upgrades. Better data ownership. Better pricing. Features that Slack locks behind $15+/user paywalls.
The only question is how much longer you want to pay the Slack tax.
Ready to switch? Deploy Mattermost or Zulip on Elestio in under 5 minutes. Your CFO will thank you.