Three things decide whether a first shared channel opens on the day you planned: your plan, who may send Slack Connect invitations, and whether an approver has to clear the invite. The menu paths below come from Slack’s help pages as I read them on 2026-11-10. Slack’s approval and invitation pages cover Pro, Business+ and Enterprise, and the paths differ for Enterprise, so both are given. Where the docs are silent, this page says so rather than guessing.
Check the plan and who can invite
Group Slack Connect channels need a paid plan. Slack’s pricing page lists Slack Connect as “1:1 only” on Free and as included on Pro, Business+ and Enterprise+. List prices in USD as of 2026-11-10: Pro is $8.75 per user per month on monthly billing or $7.25 per user per month billed annually. Business+ is $18 per user per month or $15 per user per month billed annually. Enterprise+ is “Contact sales for pricing.”
Who may invite is an owner setting. On Pro and Business+, go to Admin, then Workspace settings, then the Permissions tab. Next to Slack Connect Channels, click Expand, adjust the invitation settings and click Save. Only Workspace Owners can change this. On Enterprise, the path runs from your organization name through Tools & settings, Organization settings, Slack Connect, Settings, and the Channels tab. Find “Sending channel invitations”, click Edit, then Save Setting. Org Owners and Org Admins can change it there.
Next, pick the permission level for the external person. Slack names two:
- Permission only to post. The person can send messages, use reactions, add files, use workflows and edit the channel layout.
- Permission to post, invite, and more. Everything above, plus adding other people from organizations already in the channel, adding apps and workflows, converting the channel to public or private, setting a retention policy, and seeing an archived copy if their organization is removed.
Decision rule: if the customer’s team needs to bring in its own colleagues, pick the second level. If the channel is only for the customer to reach your team, pick the first. Name, topic, description, public or private, and retention changes made by an external person apply only to the workspace where they were made. Even so, the second level gives the customer more reach than you may want on day one.
Create the channel and send the invite
Creating the channel is ordinary channel creation. On desktop, click the plus sign in the sidebar, select Channel, enter a name, choose public or private and click Create. Slack’s docs say members can create channels by default, that Workspace Owners can change that permission, and that creating a channel is available on all plans. The Blank channel option, rather than a template, needs a paid plan. The plan limit bites at the next step, when you invite an outside organization to a group channel.
Name the channel for the account, for example ext-acme-support. That naming is my convention, not Slack’s. A private channel is the safer default for a customer, since you choose who is in it.
Then invite. On desktop:
- Open the channel and click its name in the header.
- Select the Settings tab, then click Add people under Slack Connect.
- Type the person’s email address or name and confirm with Add.
- In the next step, select the “An external organization” option, then continue with Next.
- Pick the permission level and click Next.
- Add an optional note and click Send Invitation.
On mobile, tap the channel name, tap Add, enter the contact, tap Add again, select “An external organization”, tap Next, choose permissions, tap Next, and tap Send invitation. The mobile steps do not mention the Settings tab.
Two limits matter. You cannot add external people to #general or #all-companyname. And a Slack Connect channel can host up to 250 organizations, including your own. For a one-to-one conversation instead of a channel, open Home, then Directories, then External, click Start a DM, enter the email address and click Send Invitation. You may be prompted to verify your email before sending Slack Connect invitations.
Use the optional note to tell the customer what to do next: “We’ve opened a shared channel so you can reach our support team directly. Accept the invite under Directories, then External, and tell me if your admin needs to approve it.”
Handle the approval step
If your workspace requires approval, the invite becomes a request. Slack’s approval page lists four settings, with the same names on Pro, Business+ and Enterprise: “Who can approve requests and manage Slack Connect channels”, “When approval is required for Slack channels”, “Where requests are sent for approval” and “When invitations can be automatically accepted.” The page does not list the options under each one, and it does not describe a single on-off switch. Open the section and read what is set before you promise a customer a same-day channel.
The path on Pro and Business+ is Admin, Workspace settings, Permissions, Slack Connect Channels, Expand, then choose settings and Save. On Enterprise, go from your organization name through Tools & settings, Organization settings, Slack Connect, Settings, the Channels tab, then under Approvals pick a setting and click Edit.
Approvers are Workspace Owners and Admins, and anyone they have granted permission. The review path on Pro and Business+ is Home, your workspace name, Tools & settings, Manage Slack Connect Invitations, then the Open requests tab. Click the three-dots icon next to the channel name to approve or deny. To act in bulk, select up to 25 requests, then select Approve or Deny. On Enterprise, the path is Home, your organization name, Tools & settings, Manage Slack Connect Invitations, Invitations, then Open requests.
If you are the sender and lack approval rights, post the customer’s name and email address in your internal support channel and ask an approver to check Open requests. An invite that has not bounced is not an invite that was accepted.
What the customer does
On desktop, the customer opens Home, then Directories, then External. If Directories is not there, the External connections tab in the sidebar does the same job, possibly under More. They click Accept, review the channel settings, and click Accept and Join Channel. If several people at their company get the invite, only one needs to accept it.
On iOS, they tap their profile picture, then Invitations to connect, then Accept, choose the workspace the channel should belong to, review the channel settings and tap Confirm. Android is the same, except the menu item is Slack Connect invitations.
Two gates sit on the customer’s side. Their admins may need to approve invitations they accept, and their owners and admins can restrict who may accept. By default guests and Frontline Members cannot accept. If the invite is stuck there, send: “Your admin may need to approve this Slack Connect invite before you can accept it. Could you forward it to them?”
What about a customer on a Free workspace? Slack’s pricing page lists Slack Connect as 1:1 only on Free, and the accept page marks the feature “Available on paid plans” and says an unpaid workspace may see an upgrade or free-trial prompt. The pages I read do not say outright whether a Free workspace can join a group channel you created. Ask the customer’s admin to try the invite before launch day, and have a Slack Connect DM ready as a fallback.
Confirm the customer actually joined
The docs I read give no member-by-member join notice. The check Slack documents is on desktop: open the channel, click the channel name in the header and look in the Organizations section. If the customer’s organization is listed, they have accepted. If it is missing, go to Home, Directories, External, View invitations and see whether your invite is still pending. Then ask the customer to post one test message and confirm you see it.
Failures and the fix
The invite is rejected, stuck pending or nobody responds
Slack’s approval page does not say what the sender sees when a request is denied, so do not wait for a rejection notice. Work through this order:
- Check Open requests for the channel. If the request is there and pending, ask the approver to act on it.
- If it is not there, check your own sent invitations: Home, Directories, External, then View invitations.
- If the invite is pending and wrong, revoke it. Hover over the invitation, click the revoke icon and select “Revoke” to confirm. The docs describe revoking only for invitations that have not been accepted yet. Anyone with permission to manage Slack Connect channels can revoke pending invitations sent by someone in your organization. To clear many, the Sent invitations tab has “Revoke all invitations” and “Revoke selected invitations”.
Slack’s pages do not mention an invitation expiry period, do not cover resending, and do not say whether a re-sent invite appears a second time in Open requests. So treat a second invite as a new one: revoke the first, then send once, to the address the customer confirmed.
Worked example: you send an invite at 9 am on a Monday. The approver is away, and the request is still in Open requests on Tuesday morning. Ask the approver to act, or ask an owner to approve. If it was denied, get the reason from the approver before you send another.
The channel lands in the wrong workspace
On iOS and Android the customer chooses a workspace before they tap Confirm. A customer who picks a personal workspace, or one belonging to another team, puts the channel there.
Ask the customer to read the workspace name back to you before they tap Confirm. If the invite is still pending and they are on the wrong workspace, revoke it and send a new one. The pages I read do not say how to move an accepted channel to another workspace, so contact Slack support before you rebuild the channel.
You hit the guest account limit
This happens when you invite someone as a guest instead of through Slack Connect. You can add up to 5 guests for every paid active member, so a workspace with 10 paid members can invite up to 50 Single-Channel Guests. Multi-Channel Guests are billed as regular members. Guests are available only on paid plans.
Decision rule: if the person works at another company, invite them through Slack Connect. Slack’s own admin resource says unlimited channels and Slack Connect DMs can be shared externally at no cost, and calls Slack Connect the better fit for customers, vendors and partners. Use a guest for a contractor or temporary collaborator who is not a full member and is working on a defined project, and set an end date: owners and admins can choose automatic deactivation after a set time, a custom deactivation date, or indefinite access. Slack’s guest page describes guests as people with “limited access to your company’s Slack workspace”, and sets them against Frontline Members, who are your own staff. Your employees should not be guests.
Add a second company and close the channel
To let an additional organization join, open the channel, click the channel name, select the Settings tab, and under Organizations click Add people. Check “Let additional organizations join this channel” and click Done. Someone from the invited organization must allow it, and the feature is available on paid plans. Check with the customer before you let their parent company or a vendor in.
Slack’s help pages I read do not describe removing an external organization from a channel or ending a Slack Connect channel. They cover revoking pending invitations only. Do not promise a customer a removal or archive step in your engagement terms until you have run it once in your own workspace.
Keep the channel useful after day one
Put the owner in the channel description so the customer sees it too, for example: “Owner: Dana (support lead). Backup: Eli. Weekend cover: none, replies resume Monday.” Then set a rule for messages nobody picks up. A workable one: if a customer message has no human reply after one business hour, the owner posts it in your internal channel and assigns it.