Working with channels between organizations

With Slack Connect, channels connect you to people working at other companies and organizations. You can talk to them without leaving Slack—or your Slack apps—behind.
While many apps, bots, and other integrations should continue to work with channels that have members from multiple workspaces and organizations, you may face unexpected quirks. The Conversation APIs manages most of the complexity for you.
- What are channels between organizations?
- How channels between organizations work
- Supporting channels between organizations
- New behavior to expect
- Shared channels by API
- Requesting a sandbox
- Known issues
What are channels between organizations?
A channel is a bridge between teams that need to work together. Instead of endless email threads or sidecar Slack workspaces, teams can use connected channels between workspaces, and organizations. These channels allow users to chat, share files, and use apps with the same cozy ease that they use to communicate with their more immediate colleagues in their workspace.
How channels between organizations work
In an ideal world, channels that connect workspaces or organizations will work just like any other channel for users. Your app should also act predictably.
Messages and files
All workspaces involved in a connected channel can read and send messages, share files, and access the history of shared channels.
Channel settings
A channel between workspaces or organizations may have different settings on each workspace it's party to.
- Channel names may differ. What's one workspace's
#do-stuff
is another workspace's#do-nothing
. It's best to make no assumptions about channel names and stick only with IDs. - One workspace might set the channel as private, while the other workspace may set the same channel as public.
- Data retention settings may differ between teams.
With all these differences in channel type settings, you must use the new Conversations API instead of existing APIs like channels.*
, ims.*
`, and groups.*
Supporting channels between organizations
Be on the lookout for minor differences in channel, message, user, team and related objects. When a channel can hold multiple teams within it, naturally you'll encounter messages and users originating from other teams.
🆕 Detecting when a channel has members from multiple workspaces or organizations
Your app can learn when channels become shared and unshared with another team by subscribing to the channel_shared
and channel_unshared
events in the Event Subscriptions tab under your Apps page.
To receive all shared events for channels or groups in a workspace, your app will need the channels:read
or groups:read
scope respectively. To receive only shared events for channels and groups your bot user is in, your app just needs the bot
scope.
Both shared events contain the ID of the channel itself in addition to the team that the channel was shared or unshared with:
{
"type": "channel_shared",
"connected_team_id": "TLL6DGUHX",
"channel": "CLZT0MJHZ",
"event_ts": "1565722340.000000"
}
It may be helpful for your app to note the connected_team_id
, as it will start receiving messages and events from users on that external team.
Users may seem strange
Your app will begin to receive messages and events from users on external teams. Information about these users will be different than users on the workspace where your app is installed.

An external member. In their profile, a member from an external team will be marked with a square status indicator next to the user name.
- External members are members on the other team that your application shares channel membership with.
- Strangers are external members on the other team that your application does not have a shared channel in common; you can find out about these members when the other team mentions them in the shared channel or shares one of their messages or files into the shared channel.
The user type object (returned by methods like users.info
) provides additional information to identify external members, while withholding some information your app may expect.
- If the user is a stranger who isn't in any shared channels, the
is_stranger
flag is settrue
. - For external members and strangers, profile data will not contain
email
even if you have theusers:read.email
scope. - For external members and strangers, profile data will not contain any locale information, even if you pass the
include_locale
flag.
Here's an example of a response from users.info
:
{
"ok": true,
"user": {
"id": "U0BNRNDKJ",
"team_id": "T07QCRP7S",
"name": "rex",
"real_name": "Devon Rex",
"profile": {
"image_24": "https:\/\/.../11662770033.jpg",
"team": "T07QCRP7S",
"display_name": "eshellstrop"
// all that other stuff
},
"is_stranger": true
}
}
Please note that when you specify a user, you need to use user id, instead of the username. With the new name-tagging feature, the username
attribute cannot be relied on as a unique identifier, and will not work with "foreign" users via the API. For example, you cannot use chat.postMessage
with a username
set to a foreign user.
A bot user 🤖 is able to DM users on all connected workspaces, as long as users are in a shared channel together.
Same channel, different setting
When a channel gains members from another workspace or organization, the channel ID remains the same but the name prefix can be different, depending on its setting- Even if the channel is set to private, the ID prefix changes from G
to C
(e.g. G1234567890
becomes C1234567890
).
Since each team in the channel can independently decide if the channel is public or private on their end, so there are some changes with the APIs too:
-
The
conversations.*
methods accept any type of channel. -
The channel type object now includes the channel type info (public, private, etc.).
-
The
conversations.info
method will provide additional information on the workspaces connected to the shared channel and the ID of the host workspace. -
Now the
channels.*
methods accept both public and private channels with appropriate permission scopes.
The channel type object (which is returned by methods like conversations.info
) tells you additional channel info. If the channel is shared, is_shared
is set true. If it is a private channel or a group DM channel, the properties, is_private
or is_mpim
is set true
, respectively.
Use the is_shared
, is_private
, and is_mpim
flags exclusively to determine the privacy and type of a given channel.
Example response from conversations.list
:
{
"ok": true,
"channels": [
{
"id": "C0A1NBPT3",
"name": "product-qa",
"is_channel": true,
"created": 1491332036,
"creator": "U0A379ZT2",
"is_archived": false,
"is_general": false,
"is_shared": true,
"is_org_shared": false,
"is_member": false,
"is_private": true,
"is_mpim": false,
"members": [
"U0A379ZT2",
"U0AU7DMHN"
],
...
},
{ ... },
]
}
Channels between organizations that are converted back to a single-organization channel
When a channel between organizations or workspaces is unshared by the host workspace, each workspace can still access channel history for all previous messages and activity. However, the channel in the disconnected workspace will be assigned a new ID, while the host workspace keeps the original channel ID.
Private channels between organizations
Channels between organizations and workspaces can be made private on a per-workspace basis. For instance, a public channel on one workspace can be shared with a private channel on another workspace. Use the Conversations API methods to work with the channels and accurately determine their privacy. channels.*
and groups.*
will not work with private shared channels.
When a workspace's private shared channel becomes unshared, its channel ID remains C
-prefixed (i.e. C1234567890
does not change back to G1234567890
) although the channel is still private, making channel prefix an unreliable narrator in determining privacy.
New behavior to expect
In general, apps work between workspaces transparently. However, due to the nature of connecting to multiple workspaces, there will be restrictions in some scenarios depending on how the service behind the app is designed. For example, a commercial app like Salesforce that's tied to a specific workspace's users won't automatically give access to the users on another workspace. The Conversations API & users.info
method should be used to determine appropriate data access of your app. As a rule of thumb, your app should default to exposing less information in shared channels to protect your users' data.
Bot users are accessible to all users on the workspace where your app is installed, and any external members in a channel between organizations where your bot is also present. When an external member messages you, the team
parameter will inform your app which team their message originated from. You can compare this to the team_id
parameter, which indicates the workspace where the app is installed. If your app typically shares sensitive information, make sure to change its behavior for external members.
Slash commands and message actions are not shared — they are limited only to the team that has installed to their team workspace. Another team needs to install them independently to be able to use them.
When your app is initiated by a slash command or message action, only the team that installed your app can invoke it, but external members can still see any information posted into channel as a result. For example, let's say Catnip inc. has installed a polling app that is initiated with a command /poll
. Users in the Catnip inc. can initiate a poll, while Woof inc. can only vote on the poll and cannot create a new poll.
Example: a shared bot that initiates with a slash command

Support strategies by feature
API | Support strategies |
---|---|
Events API |
authed_teams property for the response. |
Web API |
users.info to retrieve additional information on cross-team user ID not found in users.list . |
Incoming webhooks |
|
Slash commands |
|
Message actions |
|
Interactive messages |
|
Unfurls |
|
RTM |
|
Bot users 🤖 |
|
Conversations API
Developing with channels between organizations and workspaces effectively requires using the new Web API methods we call the Conversations API.
Requesting a sandbox
Building properly for channels between workspaces and organizations requires experiencing the unique constraints and opportunities yourself.
If you don't already have access to workspaces with the proper plan level to grant access to channels between organizations, please complete the form below to request a sandbox. We'll get back to you as soon as possible.
Known issues
We're still working on connected channels. Some features are not yet available and it's likely you'll run into a bug or three.
Here's what we know about:
🚧 Channel IDs can become unstable in certain situations
There are a few circumstances channel IDs might change within a workspace. If you can operate without depending on their stability, you'll be well-prepared for unfortunate hijinks.
In the future, we'll mitigate this unexpected transition with appropriate Events API events or other solutions.
In the meantime, be aware this might happen and use conversations.list
regularly to monitor change for known #channel
names if ID stability is important to you.
🚧 MPIM events tell little lies about channel types
In a multiparty direct message channel ("MPIM") with a foreign user, events like member_joined_channel
and member_left_channel
may dispatch an incorrect value for channel_type
.
🚧 IM Object format is not yet consistent
IM formats may differ from other channel objects for a while. We're working towards making all objects the same format.
🚧 Unsharing channels
When a channel becomes unshared, conversations.history
access for the channel may become unreliable.
🚧 Select menus may be inconsistent
Default select menus (users_select
, conversations_select
, and channels_select
) may display unexpected options in shared channels.
🚧 app_home_opened
event isn't triggered for external members
When members from the non-host workspace access the app DM, the app_home_opened
event will not be fired.
Stay tuned for future updates!