Microsoft Teams vs. Slack in 2026: Which Team Messaging App Should You Use?

Microsoft Teams is the better choice if you're already using Microsoft 365 — the integration with Outlook, SharePoint, OneDrive, and Teams Calling is unmatched, and for most organizations already paying for M365 Business or Enterprise, Teams is effectively free. Slack is the better choice for startups, product teams, and companies that prioritize developer workflow integrations (GitHub, Jira, PagerDuty, Salesforce) and don't use Microsoft 365. Teams wins on video conferencing and phone system integration; Slack wins on third-party app ecosystem, search, and user experience.