Microsoft Teams (Chat) vs Slack

Microsoft Teams (Chat)

Chat and channels are named as a core solution area and file sharing comes with real backing — up to 1 TB per user, SharePoint sites, Whiteboard, meeting recordings. But we found no public information on threading, mentions, search depth or history limits in the captured pages, so whether a decision from eighteen months ago is findable is simply not evidenced here.

Slack

Slack Connect delivers genuine cross-organisation channels, unlimited message history on paid plans, and Enterprise/AI search across stored knowledge — real 8-anchor material. But edit history, pinned items, filtered search and channel lifecycle (archive/rename/merge) are nowhere in the evidence, so it tops out just under that anchor.

Microsoft Teams (Chat)

Encryption of chats, calls, meetings and files is listed as included in the Teams versions, and a free Entra ID tier handles identity in every plan — which reads as transport and at-rest encryption with the vendor holding the keys, as far as these pages go. We found no public information on end-to-end encryption, key custody, device verification or guest scoping; the privacy statement's note that data may be used to develop and train AI models is the closest thing captured to a statement of what the vendor can reach.

Slack

Encryption at rest and in transit (vendor keys), SAML SSO down to the free tier, two-factor, information barriers and per-channel posting permissions — that's the 5 anchor. No end-to-end encryption mode, no device verification, no session revocation, and no statement of what Slack itself can read, so it cannot go higher.

Microsoft Teams (Chat)

Compliance is pointed at the Microsoft Purview suite, which the page says requires Microsoft 365 E3, and cancellation is documented to delete all associated data. We found no public information on per-channel retention, a discovery export a lawyer could use, an audit log, or admin control over analytics — for a works council conversation I could not answer a single question from what is captured.

Slack

Retention configurable at workspace, channel and other levels, audit logs, legal hold and native DLP are all evidenced — most of the 8-anchor list. But the evidence is silent on any export format a lawyer could use, on retention deletion being evidenced, and on whether activity analytics can be switched off, which caps it below 8.

Microsoft Teams (Chat)

Everything captured is a cloud subscription for 1–300 users, managed and cancelled through the Microsoft 365 admin center with annual auto-renewal; we found no public information on a self-hosted edition, an open-source core, federation, or a documented export path for the archive. On this evidence custody sits entirely with the vendor, and the only exit documented is deletion of all associated data on cancellation.

Slack

Cloud-only and proprietary: no self-hosted edition, no open-source core, no federation — Slack Connect is a feature of their cloud, not an exit. The closest things to custody are the Enterprise Key Management add-on and a Germany data-location option, neither of which hands the customer the archive, and the evidence documents no full export format at all.

Microsoft Teams (Chat)

Over 250 integrated business apps and a Copilot Studio chatbot builder included even in the small-business tiers is a genuine ecosystem, well past a handful of native integrations. But we found no public information on the developer surface itself: a documented API, webhooks, rate limits, an app permission model a customer could audit, or a sandbox — and agents are gated behind a Copilot licence rather than an open framework.

Slack

A real platform: a flexible build-your-own foundation, workflows by click or code, vendor-named integrations, SCIM provisioning, and workspace-level allow/restrict control over third-party services. What keeps it off 10 is the absence of a documented versioned API with deprecation policy, rate limits, and a sandbox in the evidence.

Microsoft Teams (Chat)

The privacy statement says personal data may be stored and processed in the user's region, the United States, and any jurisdiction where Microsoft or its service providers operate, with the EU-US privacy framework certifications as the safeguard. We found no public information on a published subprocessor list, an EU hosting commitment or an EU contracting entity, and the vendor is US-based — as this buyer weighs it, the archive's metadata is not European custody.

Slack

Salesforce Inc. of San Francisco is the vendor and contracting entity, subprocessors are unnamed in the evidence, and EU residency is a Germany checkbox that only starts at Business+ — the anchor-3 case exactly. The LLM stack runs in Slack's own AWS private cloud with no EU claim, and there is no self-hosted option that would remove the question.

Microsoft Teams (Chat)

Add-on prices are published to the cent with billing period, auto-renewal and VAT treatment — Teams Premium at "8,70 € Benutzer/Monat", Copilot Business at "18,20 €" — plus storage limits and a 7-day pro-rated refund. But the captured pages give no per-user prices for the base subscriptions themselves, and data security and compliance sits in a Purview suite gated behind an enterprise plan that is not priced here, so the annual invoice for a headcount that needs retention control is not computable from these pages.

Slack

The pricing pages do map real feature boundaries — unlimited history from Pro, SSO from free, DLP on all plans, Germany hosting from Business+, SLA response times per tier — and VAT-compliant invoices are documented. But not one per-user price figure appears in the evidence and Enterprise+ remains unpriced, so the annual invoice is not computable from this sheet.