Truecaller is a mobile app developed that finds mobile number details globally given a telephone number, who are either using this app or their phonebook contacts are synced and has an integrated caller ID service to achieve call-blocking functionality and social media integration to keep the phonebook up-to-date with pictures and birthdays. It was developed by the Swedish company True Software Scandinavia AB. The app is available for Android, iOS, BlackBerry, Symbian, Windows Mobile, and Windows Phone.
It uses crowdsourced data, which enables it to work even in countries such as the UK and India where public data is not available.