There’s a webhook for session creation, not event, you can watch for session edited and the events become included in them if using the webhook trick. If you are going that route though you might want to go full API and just create the sessions that way as you are then giving the session ID imediately after creating the session, and event IDs after creation too.

I’ve also seen folks just run a report after and get a column of all the ID’s and then use matches or time flexes to match them up.

When adding event to existing session, it does trigger ilt.session.updated webhook, but it returns only session_id and course_id without event id. Also when calling docebo rest api, the response returns session_id only. 

If using REST API: Updates an existing session in the LMS to update existing event property, Docebo deleted the existing one with same name and created new one from payload, so the event id changed. But the event id keeps same if using Docebo UI to modify the event property then save changes.

Not sure how to grab event id and modify event using same way as to grab session id and modify session. any help please?

Check your other thread, I posted the endpoints to use for sessions and events and they will return the info you are looking for when using them. 

Connecting these two threads for future folks reference:

Thanks for your answer in another thread.