What Is Slack? Everything You Need to Know in 2026

This is an independent guide. Not affiliated with or endorsed by Slack Technologies, LLC or Salesforce, Inc.

Your new manager just told everyone to "check the Slack channel." You nodded along, but you have no idea what Slack is, what a channel is, or why the whole company seems to live inside it. You're not alone. Millions of people land in a Slack workspace on their first day at a new job with zero context.

Slack is a messaging platform built for teams. Think of it as group chat with structure: organized conversations, file sharing, video calls, and connections to hundreds of other work tools, all in one place.

This guide explains what the Slack app is, how it works, what it costs, and how it compares to alternatives. By the end you'll know enough to hold your own in any workspace.

How Does Slack Work?

Slack organizes everything into a workspace, which is your team's shared home. Inside that workspace, conversations happen in three places:

Channels are the backbone. Each channel is a persistent chat room dedicated to one topic. A marketing team might have #campaigns, #social-media, and #brand-guidelines. Anyone in the workspace can browse public channels and join the ones relevant to them. Private channels exist for sensitive conversations.

Direct messages (DMs) work like any chat app. Send a message to one person or create a group DM with up to nine people.

Threads keep side conversations from cluttering a channel. Reply to any message in a thread, and the discussion stays attached to the original post. People who aren't following the thread won't see notifications unless someone @mentions them.

Picture this: Dana joins a 200-person company on Monday. Her manager adds her to six channels: #engineering, #standup, #office-random, #announcements, #new-hires, and #lunch-plans. Within an hour she can see months of conversation history, pinned onboarding docs, and who to ask about what. No one had to forward her a chain of 47 emails.

Slack also supports reactions (emoji responses to messages), bookmarks, pinned messages, and a search bar that indexes every message and file ever shared in the workspace. If someone mentioned a decision three months ago, you can find it.

What Is Slack Used For?

Slack started as an internal tool at a gaming company that pivoted away from its game and kept the chat tool. Today it's used across industries for very different purposes.

Business and remote teams:

• Daily standups and async status updates
• Project coordination across departments
• Company-wide announcements and culture channels
• Quick decisions that would otherwise require a meeting

Slack is a natural fit for remote and hybrid teams. If your team uses Slack alongside other collaboration tools, our guide to remote team Slack integration covers practical setups.

Project management: Teams use Slack channels as lightweight project hubs. Pin the project brief, connect a Trello or Asana integration, and post updates in the channel. It doesn't replace a project management tool, but it gives every project a conversation layer.

Developer teams: Slack is deeply popular with engineering teams. Connect GitHub, CI/CD pipelines, and monitoring alerts directly into channels. When a deploy fails at 2 AM, the alert lands in #incidents and the on-call engineer sees it immediately.

Education and communities: Universities use Slack for class discussions and group projects. Open-source communities run public Slack workspaces with thousands of members. Nonprofit organizations coordinate volunteers across time zones.

For ideas on extending Slack with useful add-ons, check out our list of the best Slack apps for remote work.

Key Features of Slack

Slack has grown well beyond text chat. Here are the features most people interact with:

Channels: The core organizing principle. Create a channel for any topic, project, or team. Public channels are open to the whole workspace; private channels are invite-only.

Huddles: Slack's built-in audio and video calls. Click the headphones icon in any channel or DM to start a huddle instantly. No scheduling, no meeting links. Huddles support screen sharing, and on paid plans, video with up to 50 participants. They're designed for quick, informal conversations.

Clips: Record short audio or video messages and post them in a channel or DM. Useful for async updates when a text message would be too long and a meeting would be overkill.

Canvas: A built-in document editor attached to channels. Teams use canvases for meeting notes, project briefs, onboarding checklists, and anything that needs to live alongside the conversation.

Workflow Builder: A no-code automation tool. Build workflows that do things like post a daily standup reminder, route requests to the right channel, or collect feedback through forms. No programming required.

Slack Connect: Invite people outside your company into a shared channel. Agencies, vendors, and clients can collaborate in Slack without needing access to your full workspace.

Slack AI: Summarizes channels and threads, recaps huddles automatically, and answers questions about your workspace's conversation history. Included in paid plans.

Integrations: Slack connects with over 2,600 apps including Google Drive, Office 365, Salesforce, Jira, GitHub, Zoom, and many more. Notifications from other tools flow into Slack channels so your team doesn't need to check five dashboards.

Search: Every message, file, and snippet posted in Slack is searchable. On the free plan, search is limited to the most recent 90 days of messages. Paid plans unlock the full history.

Slack Free vs. Paid: How Much Is Slack?

Slack uses a freemium model. The free plan is genuinely usable for small teams. Larger organizations usually need a paid tier. Pricing changes regularly, so check slack.com/pricing for current rates.

Free plan:

• 90 days of message history (older messages are hidden and eventually permanently deleted after one year)
• One-to-one huddles (audio and video)
• A limited number of app integrations (check slack.com/pricing for the current cap)
• 1:1 screen sharing in huddles
• Limited Slack Connect (1:1 direct messages with external people)
• No Workflow Builder (requires a paid plan)

Pro plan:

• Unlimited message history
• Group huddles with up to 50 participants and screen sharing
• Unlimited integrations
• Full Slack Connect shared channels with external organizations
• Slack AI (channel summaries, thread recaps, AI-powered search)
• Custom user groups and advanced search

Business+ plan:

• Everything in Pro
• SAML-based single sign-on (SSO)
• Data exports for compliance
• 24/7 support with 4-hour response time

Enterprise+:

• Everything in Business+
• Unlimited workspaces under one organization
• Enterprise Key Management (EKM) for custom encryption keys
• HIPAA-compliant configuration
• FedRAMP Moderate authorization (GovSlack offers JAB High)
• Data residency controls

A common question: "Do I need to pay to use Slack?" No. The free plan works fine for small teams and personal projects. The 90-day message limit is the main constraint; if your team needs to reference old conversations, a paid plan is worth it.

Is Slack Secure?

Slack encrypts data in transit and at rest by default. The platform holds SOC 2 Type II, SOC 3, ISO 27001, ISO 27017, ISO 27018, and ISO 27701 certifications. For regulated industries, Slack supports HIPAA-compliant configurations, FINRA 17a-4 compliance, and holds FedRAMP Moderate authorization.

Enterprise+ customers get additional controls: Enterprise Key Management (EKM) lets organizations manage their own encryption keys, and data residency options let you choose where your data is stored.

One thing to know: Slack workspace administrators can access and export messages, including private channels and DMs, depending on the plan and settings. This isn't a bug; it's by design for compliance and legal hold purposes. But it means your Slack DMs aren't as private as a personal text message. If something is truly confidential, keep it off Slack.

Slack also supports native data loss prevention (DLP) and integrations with third-party DLP providers for organizations that need to prevent sensitive information from being shared in channels.

Slack vs. Microsoft Teams

Slack and Microsoft Teams are the two dominant workplace messaging platforms. They solve similar problems but approach them differently.

Slack's strengths:

• More polished channel-based organization
• Larger third-party app ecosystem (2,600+ integrations)
• Better experience for connecting with people outside your organization (Slack Connect)
• Huddles for quick, informal audio/video without scheduling
• Stronger developer tooling and API

Teams' strengths:

• Bundled with Microsoft 365 at no extra cost
• Deeper integration with Office apps (Word, Excel, SharePoint)
• Built-in video meetings with larger participant limits
• Better fit for organizations already in the Microsoft ecosystem

Marco manages a 40-person agency that works with a dozen clients. His team uses Slack because every client gets a shared Slack Connect channel. Switching to Teams would mean asking clients to install Teams or use email instead. For Marco, the external collaboration angle is the deciding factor.

If your company already pays for Microsoft 365, Teams is effectively free and might be the path of least resistance. If your team values a cleaner chat experience, extensive integrations, and works with a lot of external partners, Slack is the stronger choice.

For a detailed look at Teams, see our guide on how to use Microsoft Teams. If you're evaluating alternatives more broadly, our Microsoft Teams alternatives guide covers additional options.

Slack is a trademark of Slack Technologies, LLC, a Salesforce company. This site is not affiliated with, endorsed by, or sponsored by Slack Technologies, LLC or Salesforce, Inc.

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