Slack vs Teams is the biggest messaging platform rivalry in enterprise software. Slack pioneered the modern work chat format. Microsoft Teams arrived later and rode the M365 install base to become the most-used collaboration tool by total daily users. The right choice almost entirely depends on what else you use.
Microsoft Teams
Microsoft Teams wins for organizations already on Microsoft 365. Slack wins for tech-forward companies, startups, and teams that prioritize developer integrations.
Specs Comparison
| Spec | Slack | Microsoft Teams |
|---|---|---|
| Price (paid base tier) | $7.25/user/mo (Pro) | Included with M365 Business Basic ($6/user/mo) |
| Microsoft 365 native | No (integration required) | Yes |
| Developer integrations | Best-in-class | Good but fewer |
| Video calling | Huddles + basic calls | Full Teams Meetings (better) |
| Free plan message history | 90 days | Unlimited (with M365) |
Microsoft 365 Integration
Teams is native to Microsoft 365. Sharing a SharePoint document, scheduling a Teams call from Outlook, editing a Word doc together in the Teams interface — none of this requires add-ons. For a company paying for M365 already, Teams is effectively included.
Slack integrates with M365 via apps and connectors, but it's never quite as fluid as native. Pinning SharePoint files, syncing Outlook calendar, or kicking off a Teams call from Slack requires jumping through some extra hoops.
Developer and App Ecosystem
Slack's app ecosystem is deeper and more developer-friendly. GitHub, Jira, PagerDuty, Datadog, CI/CD pipelines, custom bots — the integrations in Slack's app directory are more polished and more numerous for technical workflows.
Teams has a growing app ecosystem and Microsoft Copilot integration, but its third-party app quality lags Slack for engineering-heavy teams. Engineering orgs tend to prefer Slack; corporate and government tend to prefer Teams.
UX and Messaging Experience
Slack's messaging UX is cleaner and more thoughtfully designed. Thread organization, emoji reactions, huddles, and canvas documents feel cohesive. Users on r/sysadmin and r/devops frequently cite Slack's messaging experience as noticeably better.
Teams combines chat, video meetings, file sharing, and full phone system in one app — which creates some UI complexity. The app has improved significantly since 2020, but it still feels heavier than Slack.
Slack Strengths
- Best messaging UX in enterprise collaboration
- Superior developer/engineering integrations
- Cleaner, faster interface
- Excellent Slack Connect for external guest messaging
Microsoft Teams Strengths
- Included with Microsoft 365 — no extra cost for M365 orgs
- Native SharePoint, OneDrive, and Outlook integration
- Full phone system (Teams Phone) available
- Largest enterprise user base
Slack Weaknesses
- Paid plans start at $7.25/user/mo (Pro)
- Free plan limits message history to 90 days
- Video calls less polished than dedicated platforms
Microsoft Teams Weaknesses
- Heavier, more complex UI
- Lower developer/API-first integration quality
- Guest access for external parties less intuitive than Slack Connect
Best For
- a: Tech companies, startups, and engineering teams that want developer-first integrations and the best messaging UX
- b: Organizations already paying for Microsoft 365 who want a fully integrated collaboration suite without extra cost
FAQ
Can Slack and Teams users message each other?
Slack Connect allows direct messaging between Slack and Teams users. Microsoft Teams also supports guest access. Cross-platform messaging is possible but requires setup on both sides.
Is Teams free?
Teams has a free plan with basic chat and meetings. The full-featured version is included with Microsoft 365 Business Basic at $6/user/mo.