Slack introduced Slack Connect on June 24, 2020, allowing up to 20 companies to use a single channel, according to CIO Dive’s launch report. Staff moving partner conversations into Slack need to know who can see the discussion in each company. Slack’s existing shared-channel design lets each workspace choose privacy on its own side. Marking a channel private in one organization therefore does not establish how the partner has configured it. [S4][S2]
Shared channels already linked two organizations before this expansion. In an engineering account published in September 2019 and updated June 18, 2020, Slack described how people from both companies could exchange messages and files without continually adding outside guests to one company’s workspace. That account explains the preceding two-company design, rather than documenting the implementation of the new 20-company rollout. [S2][S4]
Slack’s engineers chose to keep one copy of shared-channel data rather than duplicate it for both workspaces. Messages, reactions and pins reside with the originating workspace’s channel data, while requests from the other workspace are routed to it. Yet each workspace can have its own channel name, topic and purpose, and decide whether the channel is public or private on its side. A common conversation can have different local settings. [S2]
The distinction also reaches the software used to manage channels. Slack’s older channel identifiers used a C prefix for public channels and a G prefix for private ones. Its shared-channel design uses C-prefixed identifiers even when a channel is private. Slack added an explicit is_private field and introduced the conversations.* application programming interface to replace the older channels.* and groups.* interfaces. A tool that treats every C-prefixed identifier as public can misread the setting; the prefix alone is no longer enough. [S2]
Before moving a supplier discussion into a shared channel, managers should agree on the intended audience with the partner and have both sides verify their privacy settings. That check follows from the documented design; it is not a guarantee against disclosure. Staff should be told which outside organizations are participating, rather than left to infer the audience from a familiar channel name. [S2]
Source documents
- How Slack Built Shared Channelshttps://slack.engineering/how-slack-built-shared-channels/
- Slack Connect opens channel-based communication to outside companieshttps://www.ciodive.com/news/slack-connect-launch-enterprise-collaboration/580473/