Setting up Slack Connect for external partner communication enables secure, real-time collaboration between organizations directly within Slack channels or direct messages (DMs). This feature replaces traditional email workflows with shared workspaces where teams can exchange files, hold discussions, and integrate workflow tools—all while maintaining enterprise-grade security. Slack Connect supports up to 250 organizations in a single channel and is available on all paid Slack plans, though certain features like DMs are accessible even on free plans.

Key requirements and steps include:

• Paid plan requirement: Both your organization and the external partner must use a paid Slack plan for channel-based collaboration (DMs are exempt) ^[1].
• Admin approvals: Invitations require acceptance by the external partner and may need admin approval on either side ^[6].
• Channel creation: Start by creating a public or private channel in your workspace, then invite external partners via email ^[2].
• Security controls: Customize profile visibility, app permissions, and data access for external members ^[1][10].

Setting Up Slack Connect for External Partners

Creating and Configuring a Shared Channel

To initiate collaboration, create a dedicated channel within your Slack workspace and configure it for external access. This process ensures the channel is properly set up before inviting partners, reducing administrative delays later. Begin by clicking the + button next to Channels in your sidebar, then select Create a channel ^[2][6]. Name the channel clearly (e.g., "Acme-Corp-Marketing-Collab") to reflect its purpose and add internal team members who will participate.

Once the channel is created, prepare it for external sharing:

• Channel type: Choose between public (visible to all workspace members) or private (restricted to invited members). Note that external partners will only see the channel after accepting the invitation ^[2].
• App integrations: Review which Slack apps (e.g., Google Drive, Zoom) will be available in the channel. Some apps may have limited functionality in shared channels due to cross-workspace restrictions ^[1][10].
• Custom emoji and settings: Decide whether to allow custom emoji sharing with external partners, as these will be visible to all connected organizations ^[1].

After configuration, proceed to invite external partners by:

• Clicking the channel name to open its details.
• Selecting Invite people to [channel name].
• Entering the email addresses of external contacts (ensure these are their Slack-associated emails) ^[2].
• Choosing An external organization when prompted, then sending the invitation ^[2].

The external partner will receive an email invite and must accept it within Slack. Their admin may need to approve the connection before the channel becomes active ^[6][8].

Inviting Partners and Managing Access

The invitation process is critical for establishing secure and functional Slack Connect channels. After sending an invite, the external partner will receive an email with a link to join the channel. Their acceptance triggers a series of steps:

• Partner-side approval: The external user’s Slack admin must approve the connection if their workspace has restrictions enabled. This step is automatic in some workspaces but may require manual review in others ^[8].
• Notification system: You’ll receive a Slack notification when the partner accepts the invite. Until then, the channel will display a "pending" status ^[2].
• Access levels: External members can participate in conversations, share files, and use approved apps, but they cannot modify channel settings (e.g., renaming or archiving) unless they are from the organization that created the channel ^[1][10].

To manage ongoing access and security:

• Profile visibility: Control what external partners see by adjusting profile settings. Options include hiding email addresses or limiting custom status visibility ^[1].
• App restrictions: Some apps may not function in shared channels due to data privacy policies. For example, a project management app might block external users from viewing sensitive tasks ^[10].
• Revoking access: If a partnership ends, admins can remove external members from the channel via the Member list in channel details. This action is immediate and irreversible ^[8].

For direct messaging (DMs) with external partners, the process is simpler:

• Navigate to Direct Messages in your sidebar and click the + icon.
• Enter the external contact’s email address and select Send invitation.
• DMs do not require a paid plan for either party, but both must use Slack ^[1][4].

Security and Administrative Considerations

Slack Connect incorporates multiple security layers to protect data and streamline collaboration. Key features include:

• Enterprise-grade encryption: All messages and files shared in Slack Connect channels are encrypted in transit and at rest, meeting compliance standards like SOC 2 and GDPR ^[3][6].
• Spam and phishing protections: Slack verifies external organizations before allowing connections, reducing the risk of malicious actors joining channels ^[3].
• Admin dashboards: Workspace admins can view all active Slack Connect channels, external members, and pending invitations via Settings & administration > External collaborations ^[8].
• Data retention policies: External messages are subject to your workspace’s retention settings, but partners may have different policies for their copies of the data ^[10].

Administrators should also be aware of:

• Connection limits: A single channel can include up to 250 organizations, but performance may degrade with excessive connections ^[1][9].
• Custom permissions: Enterprise Grid customers can set granular controls, such as restricting file uploads or disabling profile visibility for specific connections ^[8].
• Audit logs: All Slack Connect activities (e.g., invitations sent, access revoked) are logged for compliance and troubleshooting ^[8].

For organizations using Slack on the Enterprise+ plan, external partners on free plans can join Slack Connect channels without upgrading, simplifying onboarding for smaller vendors or clients ^[3].