Find and Join a Public Channel

You can find available public channels in several ways, depending on the Slack app you’re using.

Search via the Quick Switcher

In the desktop and web apps, press the Quick Switcher keyboard shortcut (⌘-K/Control-K), then start typing to find matches for channels (Figure 71). In any app, start typing in the “Jump to” field at the top of the main sidebar. Click the name when it pops up, and you jump to “preview” mode, discussed next.

The Quick Switcher lets you find public channels and private ones to which you belong, public channels you can join, and all users with whom you can communicate and all the conversations you’re part of.

Join a Private Channel

To join a private channel, someone in the channel has to invite you, either when they create the channel or at a later point. (If you create the channel, you’re obviously already a member.)

Slack notifies you when you’ve been invited in a subtle way: the private channel’s name appears in the sidebar’s channel list, highlighted in bold and with a number indicator (Figure 72).

It’s not so much an invitation as a command performance. You’ve already been added to the channel, and selecting it in the sidebar just explains a little about what happened (Figure 73). You have to Leave a Channel to stop being a member of it.

View Your Channels

After you’ve joined a channel, it appears alphabetically within one of these groupings in the main sidebar:

• Starred channels: These channels always appear in the Starred category at the top. (I describe how to star a channel just ahead, in Star a Channel or Conversation.)

• Channels: All apps have a Channels heading following the Starred category. It lists public channels, and in the desktop and web apps, it also lists private channels. (Private channels have a padlock icon instead of a hash .)

• Muted channels: Under each heading, muted channels appear below unmuted channels. (For more on muting, see Set Notification Preferences.)

In the desktop and web apps, you may see a red badge to the right of a channel’s name in the sidebar. The number in the badge indicates how many unread messages contain your handle or name, or any of your highlight words.

Star a Channel or Conversation

To keep favorite channels and conversations within easy reach, you can “star” them, which places them at the top of the main sidebar. To star a channel or conversation, first select it in the sidebar. Then, in a desktop or web app, click the star icon that appears under its name on the toolbar (Figure 74). (For an unstarred channel, the icon outline is gray ; when you hover directly over it, it turns gold .) In a mobile app, first tap the channel or conversation name, then tap the star icon. Once starred, it appears a solid .

Your new favorite appears alphabetically in the Starred category, which lists channels at the top and conversations below. To un-star a channel or conversation, click or tap its star icon again.

Build a Public Channel

You may want to create a new channel when conversation starts to overwhelm a given channel, even with liberal use of threads. Channels let you break down bigger conversations into ones that are topic focused, which makes sense if not all participants in a bigger channel need to be involved.

You start by creating the channel and then typically invite participants.

Create a Public Channel

The mechanics of creating a public channel are simple:

• Desktop and web apps: Click the Add button next to the Channels heading in the main sidebar to see the “Create a channel” dialog (Figure 75). Enter a channel name and specify the channel’s purpose. (I give advice on naming and specifying a purpose after these steps.) Click Create. You’re then prompted to add members; you can click Skip for Now if you’re not ready.

  

• iOS/iPadOS: Tap the channels icon, then tap the Add button next to the Channels heading. Tap Create, fill in the provided fields, then tap Create again.

• Android: Tap the workspace avatar, then tap the Add button next to the Channels heading. Tap the giant plus button in the lower-right corner. Fill in the provided fields (Figure 76). You can optionally invite members. Finally, tap Create.

You can name a channel anything, so long as it conforms to Slack’s rules: no more than 80 characters, all lowercase, and no spaces or periods. (Android limits names to 22 for no good current reason.)

Consistent naming will help your group if it has more than a handful of channels. Remember that channel names appear alphabetically in the various sidebar lists and autocomplete menus. A scheme that takes this fact into account will help other workspace members find the right channel quickly.

For instance, if your workspace has multiple departments, it might use a prefix, like acct for accounting and edit for editorial. Then instead of #general-accounting and #general-editorial channels, which sort by “general,” you’d see #acct-general and #edit-general, grouping them with other channels relevant to each department.

To provide additional cues to people looking at channels, you can fill out the purpose above, which is a general description of its intent. Any member can revise it. (Slack allows a topic, too, only seen within the channel. See Set the Purpose and Set a Topic, both later in this chapter, for more.)

Create a Private Channel

To start a private channel, use the same process described above (start by clicking the Add button next to the Channels heading in the main sidebar), but flip the “Make private” switch on in a desktop or web app or set the Public switch to off in mobile apps.

After the channel is created, only people invited to the channel even know it exists, and can search its available archives and invite other people. Leaving a private channel blocks your future access—you have to be re-invited to get back in.

Because people who you’ve invited to your channel may not notice it right away, unless you’ve already coordinated with them, you should either message them privately or write a message in the channel with an @mention to make sure they’re aware of it. The @channel message will show up as a notification for any channel members who have that sort of notification enabled.

Invite Others to a Private Channel

Nothing prevents a full workspace member in a private channel from inviting others—the mechanism is exactly the same as for public channels, described just above in Invite Others to a Public Channel.

However, each time a new person is invited, the member issuing the invitation is first offered a choice about allowing access to the channel’s message history (Figure 78).

If you agree to add a person or people to the existing channel, the previous message history is available to the new participant or participants, and the channel persists with all the same parameters.

Opt to create a new channel and Slack archives the existing channel, makes a link visible to the original participants, creates a new channel with the same name and member list as the original, and adds the just-invited person or people to that channel.

Set the Purpose

A channel’s purpose is the general description or goal of the channel. You can set the purpose for a channel when it’s created in the desktop or web apps, and anyone can edit it in any app. This can help people decide whether to join a channel, and better guide discussion within a channel.

To see a channel’s purpose:

• Desktop, web, and Android apps: Click or tap the Channels heading in the sidebar to see the channel directory. Each channel’s listing includes its purpose if one exists.

• Desktop and web apps: Select a channel in the sidebar and click the Channel Details button on the toolbar. Open the Channel Details heading in the sidebar that appears on the right.

• Mobile apps: At the top of the message list, tap the channel’s name, and the Info view (iOS/iPadOS) or “Channel details” view (Android) shows the purpose.

To set or edit the purpose:

• Desktop and web apps: Click the Channel Details button on the toolbar, expand the Channel Details section of the sidebar. Hover over Description and click “edit.” Make changes and click “Update description” or click Cancel.

• Mobile: At the top of the message list, tap the channel’s name, then tap the Edit link below the topic and purpose. When finished editing, tap the Done link (iOS/iPadOS) or Save link in the upper-right corner.

Set a Topic

A channel’s purpose, covered just above, is about the overall long-term goal for the channel, whereas its topic is more a reflection of its current focus. It can be a mood, project, idea, or joke—regardless, it should be brief, as it typically appears where just a few words can be shown.

In the desktop and web apps, the topic appears on the toolbar underneath the channel name (Figure 79); in the mobile apps, tap the channel’s name at the top of the message list to open the Info view (iOS/iPadOS) or “Channel details” view (Android). The topic shows up at the top.

To set the topic:

• Any app: The easiest way to set the topic is to open the message list for the channel, then type /topic in the Message field, followed by the new text. Then press Return or Enter (desktop/web), or tap the Send button (iOS/iPadOS) or Send button (Android).

• Desktop and web apps: Hover over the topic and click anywhere on it or click the Edit link. Edit the text, then click “Set topic” or press Return or Enter to accept. Click Cancel or press Escape to leave the topic unchanged.

• Mobile: At the top of the message list, tap the channel’s name, then tap the Edit link below the topic and purpose. When finished editing, tap the Done link (iOS/iPadOS) or Save link (Android).

Pin Messages

Sometimes you want to attach a message to a channel or conversation so that you and others can refer to it later. Slack calls this pinning.

Click the “More actions” button as you hover over any message in a desktop or web app, and choose “Pin to channel” (or “Pin to this conversation”). In a mobile app, hold down on the message, then tap Pin to Conversation (Android) or Pin Message (iOS/iPadOS).

To see pinned messages in desktop and web apps, click the pin icon on the toolbar, which displays a number next to it indicating the total number of pinned items. This opens Channel Details and expands the Pinned Item section. In iOS and iPadOS, tap the conversation name, then tap Pinned. In Android, tap the conversation name and pinned items are listed in then main “Channel details” view.

You can remove a pinned message by clicking its hover-over in the Pinned Item section and then clicking “Removed pinned item.” In iOS and iPadOS, hold down on the pinned item and tap Unpin from Conversation. In Android, hold down on the pinned item and tap Remove.

Make Announcements in a Channel

Sometimes you need to shout and be heard by everyone! For channel-wide announcements, Slack provides three special account names:

• Refer to @channel and every member of the channel gets a notification and sees a highlight in the message list, regardless of whether they are active or away.

• If you want to poke just those people currently active in the Slack conversation, @here notifies just those people. (For how Slack figures out who is “active,” see Make Your Presence Known.)

• @everyone can be used only in the #general channel. It’s the Hey, Rube! of Slack that signals every workspace member, regardless of status.

Although those announcement handles alert everyone by default, Slack lets each workspace member determine how they receive alerts in the desktop, web, and mobile Slack apps, either by channel or time of day (see Control Slack Notifications). So while each of these special handles ostensibly notifies everyone who meets the given parameters, not everyone may receive the notification right away. Slack also warns you when you try to use an announcement that would affect a lot of people, especially across time zones.

With paid workspaces, an administrator or user (if an admin allows it) can create and populate user groups that act like @channel for the members assigned to each group. So a company might have a group called @marketing, and using that handle in a message would notify all the members of that group.

If you have permission to manage groups, you can make changes in the desktop and web apps by clicking the More Items button on the toolbar, choosing Workspace Directory, and selecting the Groups tab. On the tab, click Edit User Groups or Add a New User Group.

Think carefully about how you use each of these handles. You can wind up pinging a whole lot of smartphones and computers, and thus cause people to become sufficiently annoyed with you—or with Slack in general—that they end up interacting with the workspace much less.