Slack vs Microsoft Teams: Which Team Messaging App Should You Use?

Slack and Microsoft Teams both promise to replace email for internal communication — but they serve different kinds of organisations. Here's an honest comparison to help you choose.

By Wisdom Snake Editorial Team | Published June 5, 2025

How Slack and Microsoft Teams free plans actually differ in practice Which platform has better integrations, and why it matters for your workflow Where Microsoft Teams pulls ahead for Office-heavy organisations How to decide which is right based on your existing tools and team culture The Two Giants of Team Messaging Slack launched in 2013 and essentially created the modern team messaging category. Microsoft Teams launched in 2017 and, bundled into Microsoft 365, quickly caught up in user numbers. Today both are mature, reliable platforms — but they serve different types of organisations best. The decision often comes down to one question: are you already in the Microsoft ecosystem? Free Plans: What You Actually Get Slack's free plan stores only the last 90 days of message history and limits you to 10 integrations. Audio and video calls are limited to 1:1. For a small team that just wants to try it, these limits are acceptable short-term but become frustrating quickly once important messages scroll out of history. Microsoft Teams' free plan (available without a Microsoft 365 subscription) includes unlimited message history, group audio and video calls, and 5 GB of shared storage per user. On paper, Teams' free plan is more generous. In practice, the interface can feel heavy for small teams not already using Microsoft products. Slack's paid plans start at $7.25/user/month (Pro) with unlimited message history and unlimited integrations. Microsoft Teams is included free with Microsoft 365 Business Basic ($6/user/month), making it effectively the lower-cost option if you need email and productivity apps anyway. Integrations: Slack's Historical Advantage Slack has over 2,600 native app integrations in its marketplace — essentially every SaaS tool your team uses has a Slack integration. Notifications, approvals, and status updates from tools like GitHub, Jira, Salesforce, Google Analytics, and hundreds of others flow naturally into Slack channels. Microsoft Teams has a smaller integration library but covers most major tools. Its deeper point is the native integration with the entire Microsoft 365 ecosystem: SharePoint, OneDrive, Planner, Loop, and Azure DevOps all work seamlessly within Teams without requiring third-party connectors. If your stack is Microsoft-heavy, Teams' integrations feel more cohesive, even if fewer in number. Video Calls and Meetings Slack Huddles are lightweight, always-on audio channels designed for quick conversations — more like walking to someone's desk than scheduling a meeting. For longer, structured calls, Slack's built-in video is functional but basic. Microsoft Teams is built around formal meetings. Its meeting features are significantly richer: breakout rooms, live captions, meeting recordings, transcripts, noise suppression, and a dedicated Meeting Notes feature. For organisations that run many formal internal meetings or client calls, Teams is noticeably more polished in this area. Search and Organisation Both platforms use channels (Slack) and channels within Teams (Microsoft Teams) to organise conversations by topic, project, or department. The structural difference is that Microsoft Teams adds a layer of "Teams" above channels, which maps well to departments or projects in larger organisations but can feel bureaucratic for a 5-person company. Slack's search is fast and excellent. Teams' search has improved but still trails Slack on finding specific messages quickly across large message archives. Avoid running both Slack and Teams simultaneously at your company — the result is fragmented communication, duplicate notifications, and confusion about where important decisions live. Pick one and commit. Which Should You Choose? Choose Slack if: you are a startup or tech-forward company, your tool stack includes many non-Microsoft SaaS products, your team culture values asynchronous communication and quick channel-based discussions, or you are not already paying for Microsoft 365. Choose Microsoft…

Frequently Asked Questions

Is Slack free for small teams?

Slack has a free plan, but it limits message history to the last 90 days and restricts integrations to 10 apps. For a small team experimenting with team messaging it works, but most growing teams hit the limits within a few months. Slack Pro (from $7.25/user/month) removes these limits.

Can Slack integrate with Microsoft 365?

Yes. Slack has integrations for Outlook, OneDrive, SharePoint, and other Microsoft 365 apps. However, the integration is not as seamless as using Microsoft Teams natively within the Microsoft 365 ecosystem.

Does Microsoft Teams require a Microsoft 365 subscription?

No. Microsoft offers a standalone free version of Teams that does not require a Microsoft 365 subscription. However, Teams is also included in all Microsoft 365 Business plans, making it the natural choice if you are already paying for Microsoft 365.