European alternatives to Slack.

Slack is the default team-messaging platform for a generation of startups and modern enterprises, and since 2021 a subsidiary of Salesforce, with the consolidated entity headquartered and operated from the United States. The platform runs on Salesforce / AWS US infrastructure, and the ownership structure places sub-processors under CLOUD Act jurisdiction. For a German procurement team writing a Schrems II transfer impact assessment, or a European law firm worried about discoverability of internal communications, that profile is what sends buyers looking for who legally owns the alternative, where the data physically sits, whether messages are end-to-end encrypted, and whether it holds a recognised European compliance framework (ISO 27001, BSI C5, EUCS, SecNumCloud).

This page maps the three European team-messaging tools that clear that bar against Slack: Stackfield, Element/Matrix, and Wire, each sourced to the vendor's public DPA or verified documentation.

Where your messages physically live is the fastest way to sort between them. Stackfield is the closest UX match to Slack with documented German hosting (Germany, Munich, EU-owned, CLOUD Act exposure: None), Element/Matrix is the open-protocol option preferred by sovereignty-leaning public-sector buyers (UK, open source, EU-hostable), and Wire is the enterprise standard for end-to-end encrypted team messaging (Switzerland, Swiss data residency). Team messaging is a thinner European category than email or storage; the three here meet our editorial bar, but the supply is narrower than the Dropbox or Mailchimp landscapes.

• Channel-and-thread message model (every alternative supports it).
• Direct messages, group messages, and reactions.
• File attachments with preview.
• Search across message history (Element/Matrix is the deepest here thanks to the federated index).
• Bot and webhook integrations on every alternative for inbound webhooks; Stackfield and Element have an integration marketplace approaching Slack's depth.
• Mobile and desktop clients across all major platforms.

The ecosystem is where the gaps show up:

• Slack's third-party integration ecosystem. Slack has 2 000+ apps in its directory; Stackfield has ~30 native + Zapier; Element has the Matrix ecosystem (federation with other Matrix servers is the headline feature here, not third-party SaaS connectors).
• Some of Slack's polished onboarding and template gallery for new workspaces. European alternatives let you build workspaces from scratch with less hand-holding.
• Slack AI (summary, search assistant). European alternatives ship without LLM-based features by default; adding them through opt-in Mistral or Aleph Alpha integration is possible on self-hosted Element setups.
• Native Salesforce CRM integration, replaced by Zapier or a custom integration if you keep Salesforce, or replaced by the EU CRM you switched to (e.g. Pipedrive, Teamleader, centralstationCRM; see the HubSpot alt-to page for that switch).

Moving a workspace off Slack comes down to six steps, roughly in this order.

1. Export your Slack workspace data. On a paid Slack tier, go to Settings → Workspace Settings → Import/Export Data. Take the full ZIP export, not just public channels. Private channels and DMs require workspace owner permissions plus user consent on the Pro tier; on Plus / Enterprise, owners can export everything. Keep this ZIP as your historical archive; most teams find that 80% of older messages were context-irrelevant within a year anyway.
2. Identify your "live" channels. Most Slack workspaces have 50–200 channels but only 10–30 see weekly traffic. Use Slack's analytics page (Settings → Workspace Settings → Analytics) to identify channels with recent messages. Migrate only those; archive the rest to the historical ZIP.
3. Stand up the new tool with the same channel names. Recreate your top 15–30 channels with the exact same names as Slack. This is the single biggest factor in team-adoption speed: when people open the new tool and see #general, #engineering, #marketing in the sidebar, mental adjustment is minimal. Stackfield's "Channels" map directly; Element/Matrix calls them "Rooms"; Wire calls them "Conversations".
4. Bridge during cutover for 14 days. Element/Matrix has an official Slack bridge that mirrors a Slack channel into an Element room and vice versa. Run the bridge for two weeks so people can post in either tool and conversations stay synced. Stackfield does not have a Slack bridge; for that migration, do a clean cutover with a 2-day announcement period and a one-week parallel-running window where Slack is read-only.
5. Migrate integrations one at a time. GitHub, Linear, Sentry, PagerDuty: every team has 5–15 Slack integrations they consider essential. Recreate them one by one in the new tool. Most have native equivalents or accept inbound webhooks. Test each integration end-to-end before announcing the cutover.
6. Keep Slack in read-only mode for 30 days, not cancelled. Set the Slack workspace to "no posting" with a pinned message saying "we've moved to [new tool]". This lets people search old messages without confusing the active conversation. Cancel Slack only after the read-only window has surfaced any forgotten integrations.