How do you manage an organization using both Slack and Teams?

Give each tool a clear job. One workable setup is Slack for internal messages and Teams for meetings. Another is Slack internally and Teams for communicating with clients.

Whichever split you choose, write it down somewhere people can find it. Otherwise the same conversation can end up scattered across both apps.

It can also make sense to split by audience rather than by task. Teams could be the main company platform, while technical groups use Slack when they need to work with outside organizations that use it.

That leaves two separate communication systems, not one seamless network. Be explicit about which one people are expected to check, especially when engineering and other departments need to reach each other.

Keeping both clients open is a practical option if different teams already use different tools. It doesn't require a migration, but it does mean people have another inbox to watch and have to know where to find each group.

I wouldn't assume there's a complete DM sync just because an integration exists. Check the specific product's scope and access requirements before relying on one.

If the goal is to reduce cost or confusion, picking one platform is an option too. Check what your existing Microsoft agreement actually includes and compare that with the cost of Slack. Don't assume every Microsoft subscription includes the same Teams licensing.

A switch can be disruptive, though. Start by identifying the channels and information that really need to move, rather than assuming every conversation will transfer neatly. Different groups may also have different needs, so involve them before setting a deadline.

Don't treat either app as a private space outside company oversight, or as a replacement for the helpdesk. Depending on the plan and settings, administrators may be able to export messages, including DMs. Make the retention and support-request rules clear for both platforms.