Slack
Why Slack
Slack brings team communication together in channels organised by topic, plus direct messages, voice and video huddles, and file sharing. It suits teams of any size that need real-time collaboration and quick decision-making. Teams use Slack for internal coordination and to work with external partners, running fully in the cloud.
What it does
Slack is a workplace messaging platform. Conversations live in channels organised by team, project or topic, with direct messages, huddles for quick calls, canvases for documents and lists for tracking work. Slack Connect lets you share channels with outside partners and clients.
It also has Workflow Builder for no-code automations, a marketplace of more than 2,600 apps, search across connected tools and an AI assistant, Slackbot. Slack belongs to Salesforce, so it has a native CRM connection too.
Why you would need it
Email is slow for anything urgent and bad at group work. A question to six people becomes a long thread where half the replies are lost. Decisions then sit in someone's inbox.
Slack puts the conversation in a shared channel where everyone sees the same thing. If a team needs to decide things quickly, such as a campaign launch or a sales deal, that is a real gain. It also becomes the place where alerts and updates from other tools arrive.
Where it fits
Slack is the communication layer of the stack. Your CRM, support tool, deployment pipeline and project tool send events into it, and people act on them there. A new lead in HubSpot or a failed deploy reaching a channel is a typical use.
It competes with Microsoft Teams on chat and meetings. It does not replace a project tool such as Asana or a document tool such as Notion.
What stands out
- Integrations. The marketplace lists over 2,600 apps, so most tools in your stack can post into a channel.
- Workflow Builder. Non-developers can automate routine requests, approvals and reminders without code.
- Slack Connect. You can work with clients and partners in a shared channel instead of long email chains.
- An official MCP server. AI assistants can search Slack, read and send messages and work with canvases and lists, with admin approval.
My take
As a head of growth and founder of two agencies, I have a complicated relationship with Slack. It is indispensable for fast communication and collaboration, and it is also a constant interruption that gets in the way of deep work.
My advice is to treat it as a tool with rules. Mute channels, agree when to expect a reply and keep alerts in separate channels. Used that way it is great. Left alone, it runs your day.
Verdict
Pick Slack when your team needs fast chat across functions and wants alerts and approvals from other tools in the same place. Skip it when most of your communication is with a handful of people who already use email or another chat tool well, or when you are on Microsoft 365 and Teams is already included.
Notes
Your note
Before you choose
Notification overload
The biggest cost of Slack is attention. Constant messages can derail focus. Set norms for response times, use threads and mute channels. Without them, the tool trains people to be always on.
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Plan limits for smaller teams
There is a free plan, which is useful for small teams, but it limits history, apps and features. Check what the free and lower paid plans include before you build processes on top of them, especially message history and integrations.
Price per user adds up
Slack is priced per user, and a team that includes occasional users, such as contractors, pays for each one. Review who needs a full seat. Ask how it treats guests and external partners.
Alternatives
Microsoft Teams is the natural alternative when you already run Microsoft 365. For small teams that mostly need documents and tasks, a project tool plus email may be enough.