Slack Connect vs Teams Shared Channels: Work With Another Company
Working with a client or vendor over email gets messy fast. Slack calls its answer Slack Connect and Teams calls it a shared channel. Both put people from different companies in the same channel, but the setup, the owner and the admin steps are different. Here is what the help pages say.
Miles Crawford
The quick version
In Slack Connect, one organization owns the channel and invites the others, up to 250 organizations in a channel. For channels, each organization must be on a paid Slack plan. In Teams, a team owner creates a shared channel and a shared channel owner adds people, including people outside the organization by email. Before you can add outside people, Microsoft says admins must enable B2B direct connect.
Slack Connect: channels and DMs
Slack says a Slack Connect channel can host up to 250 organizations. To work in channels together, each organization must be using a paid Slack plan. People can join the channel or be added by someone from their own organization, and people from different organizations in a channel can send each other DMs. A group DM needs everyone to be in at least one channel together. For a one-on-one conversation with someone at another organization, you can use a Slack Connect DM, which Slack says you can start on any plan by sending or accepting an invitation. If the other company does not use Slack or is not on a paid plan, Slack says you can invite them to try Slack Connect for free.
Slack Connect: who owns what
Your organization owns any channel created in your workspace. Slack says only the owning organization can invite organizations, remove other organizations, manage posting permissions, and keep using the channel if the external organizations are removed or disconnected. You can decide who can use workflows, but some workflows can never be used in Slack Connect. Apps added by another organization show that organization's Slack icon, and only people from that organization can remove the app. You can spot external conversations by hovering over the channel name, by the banner at the top, and by the External Connections section in the sidebar. To manage invitations, go to Home, click Directories, then External.
Teams: create and share a channel
Microsoft says shared channels are for collaborating with people inside and outside your team or organization. Only team owners can create shared channels, and only shared channel owners can add members or share the channel with a team. Only owners and members of a shared channel can open it, so you have to be invited. A shared channel cannot be converted to a standard or private channel, or the other way around. To share one, go to the channel, select More options, Share channel, then Share with people. Type names for people in your org or email addresses for people outside it, then select Share. People from outside your org can only be members, not owners. They get a notification and can open the channel right away.
Teams: the admin step
Microsoft says admins must enable B2B direct connect before you can add people outside your org to a shared channel. If you do not see a way to add outside people, that setting is the first thing to ask your admin about. When a team or a shared channel is created, Teams also creates a team site in SharePoint automatically.
Which one for what?
Our read: the biggest practical difference is who has to say yes first. With Slack Connect, you need a paid plan on every organization in a channel, though a DM can start on any plan. With Teams, the blocker is usually your admin's B2B direct connect setting. Check that before you promise a client a shared space. If you only need to bring in one person for a short project, a guest may be simpler, see our guest guide.
What to be careful about
- Slack Connect channels need paid plans. Each organization must be on one, but DMs work on any plan.
- The owning organization controls a Slack Connect channel. Only it can invite or remove organizations and manage posting permissions.
- Some Slack workflows never work in Slack Connect. Check before you build around one.
- Outside people are Teams shared channel members only. They cannot be owners.
- Teams needs B2B direct connect first. An admin must turn it on to add people outside your org.
- Shared channels cannot be converted. Choose the type before you create it.
Sources
Checked October 21, 2026. Limits, steps and features follow each product's own help articles. The which-one-for-what advice is ours.