If you get many calls from unidentified numbers – meaning those which are not in your Android phone’s contact list, you certainly need a caller id. One of the Android apps that you might want to consider is TrueCaller. TrueCaller is a very useful app especially if you get too many incoming calls from unknown numbers. What this app does is to show you who is calling before answering to know if the number is not saved in your Android phone’s contact list. In other words, TrueCaller Android app is a mobile caller ID that works in real time.