What Is Slack?
Slack is a channel-based messaging platform for teams, acquired by Salesforce in 2021 for $27.7 billion. With over 65 million daily active users, Slack is the communication backbone for startups, tech companies, and increasingly traditional enterprises. It organizes conversations into channels (by team, project, or topic), supports direct messaging, huddles (audio/video calls), and integrates with over 2,600 apps.
Since the Salesforce acquisition, Slack has evolved from a pure messaging tool into a "productivity platform" with workflow automation, canvas documents, AI summaries, and deep Salesforce CRM integration. The core product remains channel-based messaging, but the platform ambitions have grown significantly.
Key Features
Channels and Messaging
Channels are Slack's core organizing principle. Public channels are visible to the entire workspace; private channels restrict access. Threads keep discussions organized within channels. Bookmarks pin important links at the top of channels. Channel sections let you group channels into custom folders in your sidebar.
Message formatting includes rich text, code blocks, lists, quotes, and now Canvas - embedded documents that live alongside conversations. Scheduled messages, reminders, and custom emoji reactions add workflow utility. Slack Connect lets you collaborate with external organizations in shared channels.
Huddles and Video
Huddles are lightweight audio calls you can start in any channel or DM. Screen sharing, reactions, and threads are available during huddles. Multi-person huddles support up to 50 participants on paid plans. Video clips let you record async video messages up to 5 minutes.
Full video conferencing is not Slack's strength - most teams use Zoom, Google Meet, or Microsoft Teams for formal meetings. Slack excels at impromptu conversations and quick screen shares, not scheduled meetings with large attendee lists.
Slack AI
Slack AI ($10/user/mo add-on) is one of the most practical AI implementations in workplace software. Channel recaps summarize what happened while you were away. Thread summaries condense long discussions into key points. Search answers pull specific information from your workspace history in response to natural language questions.
Daily digests surface the most important conversations across your channels. The AI respects channel permissions - it only surfaces content you have access to. For teams drowning in message overload, Slack AI is a genuine productivity improvement, not a gimmick.
Workflow Builder
Workflow Builder creates no-code automations triggered by channel events, emoji reactions, scheduled times, or webhook events. Common workflows include: new employee onboarding checklists, standup collection, PTO requests, incident response, and approval processes. Workflows can post messages, collect form data, send to external apps, and branch based on conditions.
Integrations
Slack's app directory has 2,600+ integrations covering every category of business software. Key integrations include Salesforce, Google Workspace, Microsoft 365, Jira, GitHub, Asana, Notion, Figma, Datadog, PagerDuty, and hundreds more. The Salesforce integration has become exceptionally deep - CRM records, deals, and cases surface directly in Slack channels.
Pricing Breakdown
| Plan | Price (per user/mo) | Key Features |
|---|---|---|
| Free | $0 | 90-day message history, 10 integrations, 1:1 huddles, 1GB storage per member |
| Pro | $8.75 | Full message history, unlimited integrations, group huddles, 10GB storage/member |
| Business+ | $12.50 | + SAML SSO, data exports, 99.99% uptime SLA, 20GB storage/member |
| Enterprise Grid | Custom | + Unlimited workspaces, EKM encryption, DLP, HIPAA compliance, 1TB storage/member |
Add-ons: Slack AI: $10/user/mo. Slack Atlas (org charts): included on Business+ and above. All prices are annual billing; monthly billing is approximately 30% more. Enterprise Grid pricing typically starts around $15-25/user/mo depending on volume.
Try Slack Free - No Credit Card Required
Start Free with SlackPros and Cons
Pros
- Best UX in messaging - Intuitive, fast, well-designed
- Integration ecosystem - 2,600+ apps, best-in-class
- Slack AI - Practical summarization and search
- Workflow Builder - Powerful no-code automation
- Slack Connect - Cross-organization collaboration
- Developer-friendly - Excellent API and bot framework
- Cultural adoption - People actually like using Slack
Cons
- 90-day free limit - Message history restriction pushes to paid
- Cost at scale - 100 users on Pro = $875/mo, plus AI = $1,875/mo
- Notification overload - Can become overwhelming without discipline
- Video is basic - Not a replacement for Zoom or Teams meetings
- Performance - Desktop app can be resource-heavy with many workspaces
- AI is paid extra - $10/user on top of existing subscription
- Teams threat - Included free with Microsoft 365, puts pricing pressure
Our Verdict
Slack - The Best Messaging Experience, If Budget Allows
Slack remains the gold standard for team communication. The user experience is best-in-class, the integration ecosystem is unmatched, and Slack AI adds genuine value for information overload. Teams that use Slack love Slack - the cultural adoption rate is higher than any competitor.
The challenge is purely economic. Microsoft Teams is included with Microsoft 365 subscriptions that most companies already pay for. Justifying $8.75-12.50/user/mo for Slack on top of existing Microsoft costs is a tough sell for CFOs. Companies that value developer culture, integration depth, and UX choose Slack. Companies that prioritize cost efficiency and Microsoft ecosystem choose Teams.
Bottom line: If your team values communication quality and you are not locked into the Microsoft ecosystem, Slack Pro is worth every dollar. If you already pay for Microsoft 365, try Teams first - it might be good enough.
Frequently Asked Questions
Is Slack free in 2026?
Yes. Slack Free includes unlimited channels and members, 90-day message history, 1:1 huddles, and 10 app integrations. The 90-day message limit is the main restriction pushing teams to paid plans.
How does Slack compare to Microsoft Teams?
Slack has a better user experience, stronger third-party integrations, and a more vibrant app ecosystem. Teams is cheaper (included with Microsoft 365), has better video conferencing, and deeper Office integration. Choose Slack for developer/startup culture; Teams for Microsoft-heavy organizations.
What is Slack AI?
Slack AI ($10/user/mo add-on) provides channel summaries, thread summaries, search answers, and daily recaps. It processes your workspace data to answer questions without you reading through hundreds of messages.
Is Slack secure for business?
Yes. Slack Business+ and Enterprise Grid include SAML SSO, data loss prevention, eDiscovery, compliance exports, and Enterprise Key Management for customer-managed encryption keys. SOC 2, SOC 3, ISO 27001, and HIPAA compliance are available.
Related Reviews
Get weekly software reviews and comparison updates
Subscribe to LeadSpark Weekly