Microsoft Teams Calls with Slack

Yesterday news spread that Slack launched a new app for Microsoft Teams Calls. This integration is designed to make it seamless for your team to spin up video or voice calls in Teams—right from Slack. With this new integration, Slack is excited to give customers the same seamless calling experience that was supported for Skype and fill this known gap— but continues to be supported for other conferencing services like Zoom, Webex, etc.Here are some of the key benefits of the app:

• Remove friction from setting up a meeting – quickly launch a call in Slack with the “/teams-call” slash command. Admins can also customize call settings so anyone can start a Teams call with a quick click of the phone button in Slack. 
• Save time on joining meetings – join Teams meetings directly from calendar reminders in Slack, using the Outlook Calendar app.

Any admin with Slack app management permissions can install the app today from the Slack App Directory, it is not available in Microsoft Teams App Directory. The app is currently in beta because it’s built with Microsoft’s calling APIs, which aren’t public yet.

What about guest users which very often use Slack?
Single-Channel and Multi-Channel Guests can join calls that are initiated in channels they have access to. Only Multi-Channel Guests can initiate new calls—granted you do not have admin settings that restrict slash command usage from guests. You cannot restrict slash command usage on a per App basis. If you don’t want guests to use the /teams-calls slash command, you’ll need to restrict slash command usage for all apps by going into your app management settings for the workspace. Guest users can`t be prevented to join calls. Once the Teams call link is generated and shared in Slack, anyone can click the “Join” button to join.

So what about security standards?
After starting the call, all other activity happens and gets logged in Microsoft Teams. Slack doesn’t have any control over call security or recordings. When a user starts a meeting from Slack, Slack simply generate a new meeting link using Microsoft’s API and share it in the channel so it’s easy for anyone to join. This App does not go through a third party system prior to going to Teams. No connectors enabled in Teams for this to function correctly. Each Slack user has to individually link their Teams Account with Slack via browser-based OAuth