# What is a Slack channel?

> A Slack channel is a named room for one topic, team or client. Public, private and shared channels explained, with naming tips for ad agencies.
- **Author**: Marxx
- **Published**: 2026-11-07
- **Category**: Slack
- **URL**: https://marxx.ai/library-glossary/slack-channel

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A Slack channel is a named room inside a Slack workspace where a group talks about one topic, team or client. Channel names start with #, such as #client-northwind, and everyone in the channel sees the same messages, files and bot posts.

## The three kinds

| Kind | Who can find and join it | Use it for |
|---|---|---|
| Public | Anyone in your workspace | Agency-wide topics like #int-creative |
| Private | Only people invited | One client's team talk, leads with contact details |
| Shared | People from two or more companies, through Slack Connect | Talking with the client's own team |

A shared channel uses [Slack Connect](/glossary/slack-connect), which on Slack's free plan works 1:1 only. Paid plans include shared channels with up to 250 organisations (checked 6 Nov 2026).

## Why agencies use one channel per client

Mixing clients in one channel is how a lead gets called about the wrong brand. A channel per client keeps each client's messages, files and alerts together. A new teammate joins that one channel and sees the history of that account, within the limit of your plan. Slack's free plan keeps 90 days of message history.

## Worked example

Say your agency runs Meta ads for Sunpeak Solar. You create four channels:

- **#client-sunpeak**, private: your team's discussion.
- **#client-sunpeak-leads**, private: one message per new lead.
- **#client-sunpeak-alerts**, private: ad alerts for the media buyer.
- **#ext-sunpeak**, shared with Sunpeak's team: updates and approvals.

The client sees only the last one. Each of the four has an owner named in its description.

## Naming channels well

- Start with the type: client-, int- for agency-only, ext- for shared.
- Add the client name next, then the job: -leads, -alerts.
- Use lowercase and hyphens, and the same pattern for every client.

The full scheme is in our [Slack channel naming conventions for agencies](/templates/slack-channel-naming-conventions-for-agencies). For the bigger picture, read [how to set up Slack for an ad agency](/guides/how-to-set-up-slack-for-an-ad-agency).

We make Marxx. [Marxx in Slack](/features/slack) can send each kind of message to its own channel, set per client.

## FAQ

### Should client channels be public or private?

Private is safer for anything with lead contact details or budget talk. Public works for agency-wide topics.

### Can I rename a channel later?

Yes, but tools that post to it may need updating. Fix your naming scheme early to avoid it.

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