| Description | Slack replaces your company's internal email with organized group chats called channels. You create a channel for each project, team, or topic — so conversations stay focused and easy to find. Your team can also share files, hop on quick audio calls (called Huddles), and connect with outside partners through Slack Connect.
For a small business, Slack keeps everyone on the same page without the clutter of long email threads. Built-in tools like Canvas (shared documents), Lists (simple task tracking), and Workflow Builder (no-code automation) mean you can manage lightweight projects without paying for extra apps. And with 2,600+ integrations, Slack connects to nearly every tool your business already uses.
Slack now includes AI features on every plan — even the free one. The AI can summarize channels you missed, draft messages, answer questions about your company's conversations, and recap your day. It's like having an assistant that reads every message so you don't have to. | Email and calendar app included with Microsoft 365. Combines inbox, calendar, contacts, and task list. Professional email hosting with your company domain, shared calendars, and Focused Inbox that separates important emails from noise.
Included with Microsoft 365 Business ($6/user/month+). Free personal version at outlook.com. |
| Strengths | - •2,600+ integrations connect Slack to almost any tool your business uses — from accounting to project management
- •AI features included free on all plans, including channel summaries, daily recaps, and AI-powered search across connected apps
- •Generous free tier includes SSO (single sign-on) and DLP (data loss prevention) — security features most competitors charge for
- •Slack Connect lets you message clients, vendors, and partners directly — a feature no major competitor matches
- •Built-in project tools like Canvas and Lists reduce the need for separate document and task management apps
| - •Most widely used business email client — works with everything
- •Deep calendar integration with Teams, SharePoint, and M365
- •Robust search, filtering, and rules for high email volumes
- •Free personal version at outlook.com
|
| Weaknesses | - •Per-user pricing adds up fast — at $8.75/user/month (Pro), a 25-person team pays $218/month before add-ons
- •Free plan limits message history to 90 days — older conversations disappear, which can be a problem if you need to reference past decisions
- •Only 10 integrations on the free plan — most small businesses will hit that ceiling quickly
- •Video calls lag behind Zoom and Teams — Huddles work for quick chats but lack features for formal meetings or webinars
| - •Requires Microsoft 365 subscription — cannot buy standalone for business
- •Desktop app can feel heavy and slow
- •Interface packed with many features — can feel cluttered
- •Some security features rolling out mid-2026
|
| Key Features | - •Organize conversations into channels by team, project, or topic so nothing gets buried in email
- •Automate routine tasks with Workflow Builder — no coding needed
- •Connect 2,600+ apps like Google Drive, Salesforce, and HubSpot directly inside Slack
- •Collaborate with outside partners through Slack Connect without sharing your full workspace
- •Get AI-powered summaries of channels, threads, and daily activity on every plan
| - •Professional email with your company domain included with M365
- •Shared calendars and Scheduling Assistant for team meetings
- •Focused Inbox separates important emails from newsletters
- •Syncs across desktop, web, and mobile in real time
- •Task management via Microsoft To Do integration
|
| Pricing | Free tier available Free Tier | Free tier available Free Tier |
| AI Features | AI-PoweredSlack's AI assistant works across your entire workspace. It can summarize any channel or thread so you can catch up in seconds instead of scrolling through hundreds of messages. It gives you a daily recap of what happened across your channels. You can ask it questions — like 'What did the sales team decide about the new pricing?' — and it pulls answers from your conversations. It also drafts messages, summarizes uploaded files, and translates text into other languages. The AI even suggests automations you can build with Workflow Builder. All of these features are included on every Slack plan, including the free tier. | AI-PoweredCopilot Chat drafts emails, summarizes threads, catches you up on missed conversations, manages calendar via natural language, suggests meeting times, prioritizes inbox, generates responses. Rolling out across M365 plans in 2026. |
| STOA Verdict | Slack is the best team messaging tool for small businesses that rely on lots of apps and outside collaboration. The 2,600+ integrations and Slack Connect make it the hub where your tools and partners come together. Just watch the per-user costs — at $8.75/user/month, it can get expensive as your team grows past 15-20 people. | The business email standard — reliable, works with everything, and your team already knows it. Calendar sharing and Scheduling Assistant alone save hours weekly. Tied to Microsoft 365 subscription. |
