If you have previously registered and shared data:
You can find your sharing key in your account. Please go to ‘Account’ -> ‘My data sharing’
https://www.flightradar24.com/account/data-sharing
Sharing keys get deleted if not used for 6 months.
New?
If you have a radarcape, please email your coordinates in decimal format to support@fr24.com and a key will be created for you.