Slack Connect: what it is, what it costs and how to run customer channels in it

Most teams that sell to other businesses end up talking to customers in two places: email for anything formal, and a growing pile of shared Slack channels for everything else. Slack Connect is what makes those shared channels possible. This guide explains what it is, who pays for it, how to set one up properly, and the habits that keep a customer channel from quietly going stale.

What Slack Connect is

Slack Connect lets you share channels and direct messages with people at other companies. Each company keeps working in its own Slack workspace, and nobody gets access to the other side's workspace, only to the channels you share. To the people in it, a Slack Connect channel looks like any other channel, with one difference: the people from the other company are marked as external. Slack's developer documentation has a clear overview of how Slack Connect works if you want the detail.

In practice, it replaces the long email threads you used to have with customers, agencies and vendors. Questions get answered in a thread instead of a reply-all chain, and files sit next to the conversation about them. New people on either side can scroll up to catch up. That is also why the channels need some care: they are easy to start and easy to neglect.

Is Slack Connect free?

Partly. The company that sends the invitation needs a paid Slack plan, because inviting someone outside your company to share a channel is a paid feature. The company that receives it pays nothing to accept, and you get a notification when they join. Slack's Slack Connect page sets out who pays for what.

The plan on the other side matters too. Slack Connect channels are not available to every free workspace. If you are on a paid plan other than Enterprise+, eligible partners on a free plan get a 90-day free trial of Slack's Pro plan when you invite them. On Enterprise+, partners on a free plan can join your Slack Connect channels without upgrading or starting a trial.

Direct messages are simpler. All of Slack's paid plans include one-to-one messages with someone outside your organization through Slack Connect.

The practical upshot for a small company selling to businesses is this. If you are on a paid plan and your customers use Slack, Slack Connect costs you nothing extra. The trial is the part to watch. Before it ends, check which plan your customer will be on, because Slack Connect channels are not available to every free workspace.

How to set up a Slack Connect channel

Setting up the channel takes a couple of minutes. Setting it up so it still works in six months takes a little thought beforehand, so start there.

Before you invite anyone

Decide on the channel name first, because the other company will see it too. A consistent prefix such as ext- followed by the customer's name makes shared channels easy to spot and easy to search. Keep the name about the relationship, such as ext-northwind, rather than about a project that will end.

Next, decide what the other side should be able to do. When you invite them, you choose whether they can only post, or post and invite others. Posting only is the safer default for customers, because it keeps the guest list in your hands.

Finally, check your company's settings. Admins can restrict who can invite external people to channels, and they may need to approve the invitations you send. The other company may have the same rule on its side, so their admins may need to approve your invitation before anyone can accept it. Slack's help article on working with other companies in channels covers both sides. Telling your contact this in advance saves a day of wondering why nobody has joined.

You cannot share #general or #all-companyname with another company, so create a dedicated channel for each relationship.

Send the invitation

On desktop:

1. Open the channel and click the channel name in the header.
2. Select the Settings tab.
3. Under Slack Connect, click Add people.
4. Enter the email address of the person you want to invite, then click Add.
5. Choose An external organization, then click Next.
6. Choose whether they can post only, or post and invite, then click Next.
7. Add a short note if you like, then click Send Invitation.

Slack tells you when the other side accepts. Let your contact know the invitation is on its way, because an unexpected email from Slack is easy to ignore. For a longer walkthrough, including private channels and permissions, see our guide on how to create an external Slack channel.

When the invitation is stuck

Most stuck invitations come down to approvals or plans. Either an admin on one side has not approved the invitation, or the other company's workspace cannot use Slack Connect on its current plan. If you sent the invitation to the wrong address, you can revoke it as long as it has not been accepted yet. Our guide to Slack Connect invitations that cannot be accepted covers the usual causes and fixes.

What the other company can and cannot see

The other company sees the channels you share with them and nothing else. Your other channels, your member directory and your files elsewhere in the workspace stay private. Each side can also set the channel's privacy separately, so a channel can be private in your workspace and public in theirs.

Everyone can tell who is who. People from another company are marked with a square status indicator next to their name. It is worth a quick reminder to your own team anyway, because a message written for colleagues reads very differently to a customer.

Some things behave differently in a shared channel. Certain file types, mostly executables and archives, cannot be added to Slack Connect channels or direct messages at all. Apps also work slightly differently: a slash command only works for people in the workspace that installed the app, but everyone in the channel sees what it posts. That is worth checking before you rely on a bot in a customer channel.

For larger programs, one channel can connect up to 250 organizations. That suits a partner community or a beta group. For a single customer relationship, one channel per customer is easier to run.

Slack Connect or guest accounts?

Slack Connect is not the only way to bring outsiders into Slack. Guest accounts let you add people to your own workspace with limited access. The two solve different problems, and choosing the wrong one costs money or control.

A guest works inside your workspace, under your company's management and your company's bill. Guest accounts are only available on paid plans. A single-channel guest can access one channel, and you can add up to five of them for every paid active member. A multi-channel guest can be added to as many channels as you choose, and is billed as a regular member. Slack explains the difference in its guide to single-channel and multi-channel guests.

A simple rule covers most cases. If the other person's company already has Slack, use Slack Connect, because they keep their own account, notifications and history. If they are a freelancer or contractor without a workspace of their own, a single-channel guest is usually right. A multi-channel guest only makes sense for someone who works almost like an employee. Our comparison of Slack Connect and guest accounts covers the edge cases.

Direct messages with people at other companies

Slack Connect also works for one-to-one conversations, and all paid plans include it. A direct message is the right place for a quick question to a counterpart, or anything you would not put in front of the rest of their team.

For customer work, though, prefer the channel. A conversation in one person's direct messages is invisible to the rest of your team, so it stalls the moment that person is on holiday or busy with another account. Our guide to Slack Connect direct messages explains how to start them and when they make sense.

How to run customer channels that stay responsive

Opening a shared channel is the easy part. The channels that still work well a year later tend to have a few things in common, and none of them are technical. For coverage rotas, response targets and templates when you support many customers this way, see our playbook on Slack for customer service.

Name channels so you can find them

Use one prefix for every shared channel, and the customer's name after it. When everything starts with ext-, you can see all your customer channels in one search, sort them in the sidebar, and spot the one that has gone quiet. Avoid names based on projects or contract terms, which go out of date while the relationship continues.

Give every channel an owner

Every shared channel needs one named person on your side who is responsible for making sure questions get answered. That person does not have to answer everything. Their job is to notice when nobody has, and to hand questions to the right colleague. Name a backup for holidays, and write both names in the channel description.

Keep the internal conversation internal

Pair each customer channel with an internal one, such as int-northwind, for your team's discussion about the customer. That is where you ask "has anyone seen this bug before?" or "should we offer a discount?" It keeps half-formed opinions out of the shared channel, and it gives new teammates a place to read the history of the account.

Set a response target and say it out loud

Customers in a shared channel expect chat speed, and that expectation forms early. Decide what you can actually deliver during business hours, then tell them in a pinned message. A promise you keep every time builds more trust than a fast reply on Monday and silence on Friday.

A pinned welcome message does most of this work. Here is one you can adapt:

Welcome to #ext-northwind, the shared channel between Northwind and our team.Who answers: Priya (account manager) and Sam (support). Sam covers when Priya is away.When: weekdays, 9am to 6pm London time. We aim to reply within 30 minutes in those hours.Outside those hours: we'll pick up your message first thing the next working morning.Urgent production issues: start your message with URGENT and mention @support-oncall.Please reply in threads, so each question stays in one place.

It answers the three questions every customer has on day one: who is listening, when, and what to do if something is on fire.

The risk nobody mentions: customer messages that sit unanswered

A shared channel feels responsive right up until the week it is not. Someone asks a question late on a Friday, two people on your team see it, and each assumes the other will reply. A question lands in a thread that nobody is following. The channel owner is on holiday and the backup was never told. None of this is visible from the outside, except to the customer, who waits.

There are three ways to deal with it, and the right one depends on your volume. Small teams can run a rota with a daily sweep of every shared channel, which works until the number of channels grows. Teams that need tickets, queues and assignment usually move to a helpdesk built on Slack Connect, such as ClearFeed, Pylon, Thena or Unthread. They accept the per-seat cost that comes with it.

The third option sits in between. Follow Up Bot watches your Slack Connect channels. When a customer message passes your response target with no reply, reaction or thread answer from your side, it alerts your team privately. The customer never sees a bot, and nothing changes about how you work in the channel. If what you need is a full support desk, one of the helpdesks above is the better fit.

Common problems and how to fix them

The invitation never arrived

Confirm the email address, ask them to search their inbox for a message from Slack, and check whether an admin on either side still has to approve it. If the address was wrong, revoke the invitation and send a new one.

A file will not upload

Slack blocks some file types in Slack Connect channels and direct messages, mostly installers, scripts and certain archives. Share the file through a link to your file storage instead, which also lets you control who can open it.

A bot does nothing for the customer

Apps installed in your workspace answer to your team. When a customer runs your app's slash command, it does not work for them, even though they can see what the app posts. If an app needs to serve both sides, check its documentation for Slack Connect support before you promise anything.

Customer messages get lost

Put every shared channel in its own sidebar section, and ask everyone who covers customers to set notifications for those channels to all new messages. It is a small change that makes a customer question look different from internal chatter.

The channel has gone quiet

A silent channel is not always a happy customer. If a busy channel has had no messages for a few weeks, the owner should check in. Ask a direct question, not a generic "anything we can help with?" A quiet customer channel is often the first sign of a renewal at risk.

Ending a Slack Connect channel

Relationships end, and shared channels should end with them. To stop sharing a channel, open the channel settings and remove the other organization under Organizations. The company that owns the channel can keep using it.

What the other side keeps depends on the permissions you gave them. Organizations that could only post do not get an archived copy of the channel. Files added by members of the removed organization stop being accessible. History from before the split stays readable in each workspace that keeps a copy.

Removing an organization from one channel is different from disconnecting from that organization entirely. Disconnecting ends every shared channel and direct message with them, and it is normally an admin task. If you only want to close one project, remove the organization from that channel and leave the rest alone.

Questions people ask