Slackline allows you to share Slack channels with other teams

About Slackline

Do you need to collaborate with a client or a partner? Break down the barriers and share a channel with them using Slackline.
You will be able to create shared channels you can use to work more efficiently with other teams.

Alternatives to Slackline

Slackline is listed in: Connect to other messaging services

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Use 🍑 from Slack!
Easily update other teams about your work, through Slack. reviews applications which integrate with Slack, and is not created by, affiliated with, or supported by Slack Technologies, Inc.