@adam deltinger
its not currently built into Teams as has been discussed in this thread.
However you can create this with not too much effort using PowerAutomate and optionally a PowerApps as an input form without a need for additional licenses.
the flow can
- get the members of any group in Azure AD
- filter the list to get rid of non-enabled users and guest users
- Apply to each, for this use Settings > Concurrency = On ,
Set to 20 .. 50 to send messages in parallel
- Post a message as the Flow bot to a user
here you can set isAlert=true, and a Summary with the alert that is shown in the toast
By using the parallel / concurrent option , the time needed to send individual messages to a many different users is reduced by a factor of 20..50. each msg post seems to take in the order of 1 second.
Estimated throughput :
1000 users / 50 = 20 seconds or about 3.000 users / minute
Note that while this works well up to a couple of thousand users, I do not think you can just scale this to 100.000 users as other other restrictions will apply , such as the below.
for that scenario some additional logic will be required
Limits
| Apply to each items - Office 365 and Free licenses |
5,000 |
https://docs.microsoft.com/en-us/power-automate/limits-and-config
| Teams request type |
Limit per app per tenant |
| Any Graph API calls for Microsoft Teams |
15000 requests every 10 seconds |
https://docs.microsoft.com/en-us/graph/throttling
and in the licensing guide :
https://docs.microsoft.com/en-us/power-platform/admin/powerapps-flow-licensing-faq
| PowerApps for O365 |
daily - per license |
| Per license capacity Daily API Requests |
2.000 |
you can build on this concept by adding logging of success / failure to notify, and ask for acknowledgement and store that in a log (Excel / SPO List) or database of some kind.
see attached for a quick Proof of Concept
