This is a basic implementation of a Calendar booking app.
2 Routes :-
when user wants to create a meeting its just a simple form with link of their choice , start and end time.
other user visits the link and can choose a time slot for meetings , then a free busy query to check between those slots , if free meeting is booked and added on calanders of both users (better implementation is get the calander list between the slot and then user can choose a slot)
Duplicate link can be checked using bloom filters (not implemented)