tech from europe
vsSlack

Threema Work vs Slack

Last updated October 2026

Looking for a European alternative to Slack? Here's how Threema Work compares, on EU hosting, GDPR and what it does.

Our pick for a European buyer: Threema Work. We weight data residency, GDPR and EU jurisdiction above everything else — that is the constraint this directory exists to solve.

Threema Work
Slack
What it is
Swiss end-to-end encrypted team messenger with on-premise option
Team communication and collaboration platform with channels, messaging, and integrations.
Headquarters
🇨🇭 CH
🇺🇸 US · 2013
EU data residency
Yes, for all customers
Available on some plansEU data residency is available only on the most expensive plans.
DSGVO / GDPR
Yes
Yes
Certifications
ISO 27001
ISO 27001, ISO 27017, ISO 27018, SOC 2 Type II
Price from
No
$7.25/user/mo
Free plan
No
Yes
Open Source
Yes
No
Ratings
G2 3.7/5 (9) · CAPTERRA 4.6/5 (10) · TRUSTPILOT 3.1/5 (56)
G2 4.5/5 (28,000)
Integrations
No
Google Drive, Zoom, Microsoft Teams, Trello, Asana +5

Where each one wins

Threema Work

Review sentiment not yet compiled.

Slack

Strengths

  • +Highly customizable with extensive app integrations
  • +Intuitive interface for team collaboration
  • +Strong search functionality for past messages
  • +Reliable uptime and performance

Limitations

  • −Can become expensive for large teams
  • −Steep learning curve for advanced features
  • −Notifications can be overwhelming
  • −Limited message history in free tier

Data residency & compliance

Threema Work
Slack
EU data residency
Yes, for all customers
Available on some plansEU data residency is available only on the most expensive plans.
Transfer mechanism
Not required — data stays in the EU
Standard Contractual Clauses
DPA
not established
Published →
Sub-processors
not established
Listed →
Certifications
ISO 27001
ISO 27001, ISO 27017, ISO 27018, SOC 2 Type II

Pricing

Threema Work

No published pricing we could verify.

Slack

  • Free Free ForeverUp to 10,000 searchable messages · 10 app integrations · 1:1 voice and video calls
  • Pro $7.25 per active user/month (billed annually)Unlimited message history · Unlimited app integrations · Group video calls up to 50 participants
  • Business+ $12.50 per active user/month (billed annually)Advanced security features · Compliance exports · 99.99% guaranteed uptime
  • Enterprise Grid On request CustomUnlimited workspaces · Enterprise-grade security and compliance · Data residency options

EU data residency is only available on Enterprise Grid. Pricing for this plan is custom and requires contacting sales.

Features

Threema Work

Feature breakdown not yet compiled.

Slack

Messaging & Collaboration
Real-time messaging in channels and direct messages, Threaded conversations for organized discussions, File sharing and collaboration, Searchable message history
Integrations & Workflow
Connects with 2,400+ third-party apps, Customizable workflows with Slack Workflow Builder, Automated reminders and notifications, API access for custom integrations
Security & Compliance
Enterprise Key Management (EKM) for message encryption, Data loss prevention (DLP) integrations, Compliance with GDPR, HIPAA, and FINRA, Two-factor authentication (2FA) enforcement
See Threema Work →More Slack alternatives