Truecaller is the app for your call safety, it detect spam callers and notify you about them, I am used iphone and it is working good but not very well, because when someone unknown person call me , it not shows the name and number on trucaller pop up.
sometimes it shows but sometimes not.but in android it shows all the call details of incoming caller name and number even the number is not saved on phone memory.
that's seem good and working very well on android phones, but in iphone the true caller app is not doing good.