VolajiciInfo is an Android mobile application which allows you to see detailed information about your contact who is calling you.
The application downloads a JSON file with phone numbers and detailed information about your contacts from a URL you provide and regularly update it form the URL. When your contact is calling you, overlay dialog pops up and shows information associated with the caller number. You can also manually search for the number within the app.
The user has an opportunity to customize a behaviour of the app.