Developer-friendly chat vs the tool bundled into Microsoft 365.
| Slack | Microsoft Teams | |
|---|---|---|
| Entry paid price | Pro: $7.25/user/mo annual ($8.75 monthly) | Teams Essentials: $4/user/mo annual |
| Bundled option | None; Slack is always a separate line item | Included in Microsoft 365 Business Basic ($7/user/mo) and up |
| Free tier | Yes: 90-day message history, 10 app integrations | Yes: free Teams for home and small business use |
| Message history on free | 90 days | Not the main constraint; limits are on meetings and admin features |
| Third-party integrations | Thousands of apps, strongest directory in the category | Growing, but strongest inside the Microsoft ecosystem |
| Office suite integration | Connectors only | Native: Word, Excel, SharePoint, Outlook, Copilot |
| Cross-company channels | Slack Connect, mature and widely used | External access and shared channels, more admin friction |
| Video meetings | Huddles, lightweight | Full meeting platform with webinars and phone add-ons |
| Ownership | Salesforce | Microsoft |
| Best fit | Tech companies, startups, agencies | Microsoft 365 organizations of any size |
Published US per-user prices as of August 2026, from each vendor's pricing pages. Annual billing shown unless noted.
| Plan | Price | Notes |
|---|---|---|
| Slack Free | $0 | 90-day history, 10 apps, 1:1 huddles |
| Slack Pro | $7.25/user/mo annual, $8.75 monthly | Full history, unlimited apps |
| Slack Business+ | $15/user/mo annual, $18 monthly | SSO, compliance exports |
| Teams Essentials | $4/user/mo annual | Standalone Teams, 10 GB storage/user |
| Microsoft 365 Business Basic | $7/user/mo annual | Teams plus web Office, email, 1 TB storage |
| Microsoft 365 Business Standard with Copilot | $23.50/user/mo annual | Desktop Office apps included |
The comparison that matters: Microsoft 365 Business Basic at $7 costs less than Slack Pro alone at $7.25, and it includes email, storage, and the Office web apps along with Teams. For a 50-person company that is roughly $4,350 a year for Slack Pro on top of whatever else you buy, versus chat effectively included in a suite you may need anyway.
Pick Slack if chat is where your company actually works. Software teams, agencies, and startups tend to live in channels all day, wire in GitHub, Linear, PagerDuty, and dozens of other tools, and automate real workflows with the platform. Slack's app directory and API are still the deepest in the category, and the difference shows the moment you try to build anything beyond a notification bot.
Slack Connect is the other underrated reason. If you regularly work in shared channels with clients, vendors, or partners, Slack's external channels are mature and low-friction. In consulting and agency work I see entire client relationships run through Connect channels. The Teams equivalent exists but carries more tenant-admin friction, and in practice fewer outside companies will meet you there.
The cost is real, though. Slack is always a separate line item, its free tier's 90-day history makes it a trial rather than a long-term option, and at Business+ prices a mid-size company is spending serious money on chat alone.
Pick Teams if your organization runs on Microsoft 365, which is most established businesses over about 50 people. The bundling math is decisive: you are already paying for licenses that include Teams, so choosing Slack means paying twice for overlapping capability. IT departments also prefer managing one vendor, one identity system, and one compliance surface, and that preference usually wins.
Teams is also genuinely stronger where chat meets the rest of office work. Meetings, calendar scheduling through Outlook, co-editing Word and Excel files, SharePoint storage, and the phone-system add-ons make it closer to a communications platform than a chat app. If your company does more scheduled meetings than asynchronous channel work, Teams fits how you already operate. Copilot integration across the suite is a further pull if your org is standardizing on Microsoft's AI stack.
The honest downside: the day-to-day chat experience still trails Slack. Threading is clumsier, notification control is weaker, and power users coming from Slack will complain for months. They usually adapt, but the friction is real.
Most write-ups treat this as a product comparison when it is really a procurement question. Since Microsoft unbundled Teams from some Microsoft 365 suites after EU regulatory pressure, the exact bundling varies by region and license, so the first step is not reading reviews, it is reading your own Microsoft agreement. Many companies discover they are already licensed for Teams, and at that point Slack has to justify its full cost against a marginal cost of zero. That is the actual competitive dynamic, and it is why Teams keeps winning deployments despite Slack's better product reputation.
The second thing missed: the switching cost is not the software, it is the archive and the integrations. Years of searchable decisions live in whichever tool you adopt, and export paths between the two are lossy. Whichever you choose, you are choosing it for a long time, so weight your five-year vendor relationship more than this quarter's feature checklist.
If you can choose freely, choose Slack. It is the better communication tool and the better automation platform, and for a tech-forward company under a few hundred people I think the price is worth it. But if your organization already pays for Microsoft 365, I would not fight the bundle. Teams is now good enough that paying separately for Slack is hard to defend to whoever signs the invoices, and consolidation on one vendor simplifies security and admin. Choose Slack on merit, choose Teams on math, and know that the math wins more often.