Slack is a proprietary messaging platform operated by Salesforce, with the largest third-party app directory in the category and an interaction design most teams already know. Enclessa is open source under AGPL-3.0, hosted in the European Union, and encrypts direct messages end to end with MLS so that the operator of the service cannot read them. Slack offers customer-managed encryption keys on its top tier, which is a real control and a different thing from end-to-end encryption: the service still processes plaintext.
| Dimension | Enclessa | Slack |
|---|---|---|
| Source code | Open source, AGPL-3.0 | Proprietary |
| End-to-end encryption | Direct and group direct messages, MLS per RFC 9420 | Not offered. Enterprise Key Management provides customer-controlled keys, with the service still processing message content |
| Hosting | European Union; self-hosting on Enterprise | Operated by Salesforce, with regional residency options on higher tiers |
| Message history | Retained per your own retention policy | Historically limited on lower tiers; check the current plan terms |
| Third-party apps | None. First-party modules only, no runtime third-party code | A very large app directory |
| Included modules | Task boards, GitHub sync, time tracking, HR records | Available through third-party apps |
| Video calls | Group calls with screen sharing, lobby and host controls | Huddles, plus integrations with dedicated meeting products |
| Leaving | Full organisation export; documented data model and OpenAPI | Export tooling varies by plan |
Statements about other products come from their own public documentation and describe the position at the time of writing. Vendors change what they offer; check the current documentation before making a decision on the strength of this page.
Holding the key in your own key management service is a genuine control, and it is not the same as the service being unable to read the message. In Enclessa the server never has a key for an encrypted room, so the distinction does not depend on a configuration being right.
Where the data sits is not a feature reserved for the top tier. The service runs in the European Union for every customer.
Boards, GitHub sync, time tracking and personnel records are modules of the same platform under one permission model, instead of four subscriptions stitched together with apps.
History is kept according to your organisation’s retention rules rather than according to which plan you are on.
This section is here because a comparison page without one is an advertisement. If any of these describe you, buy the other product.
Slack’s ecosystem is its strongest asset and Enclessa deliberately runs no third-party code. If a vendor’s Slack app is central to how you work, that is decisive.
Shared channels between companies are something Slack does well and Enclessa does not offer.
Most knowledge workers already know Slack. If your rollout budget is thin and confidentiality is not a driver, that familiarity is worth money.
Create a workspace in a couple of minutes. It is yours at your-team.enclessa.app, hosted in the European Union, with encrypted direct messages from the first one you send.
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