Hello @Amir Sohail - One way is to handle the meeting events in bot and then you can call your external app's API's end point.
Reference sample code: https://github.com/OfficeDev/Microsoft-Teams-Samples/tree/main/samples/meetings-events
Other way is to create a subscription for online meeting:
https://learn.microsoft.com/en-us/graph/api/subscription-post-subscriptions?view=graph-rest-beta&tabs=http#onlinemeetings-presence
Reference docs:
https://learn.microsoft.com/en-us/graph/webhooks-with-resource-data
https://learn.microsoft.com/en-us/graph/changenotifications-for-onlinemeeting
https://learn.microsoft.com/en-us/graph/webhooks-with-resource-data#managing-encryption-keys
Thanks,
Chetan Sharma
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