mSpy and XNSPY are the best and most famous spy apps for both android and iPhone. It must be clear that these android spy apps should be used within the ethical norms. There could be hundred of reasons why one wants to keep an eye on someone’s phone. Some of the curious personals may include concerned Parents, Teachers or even spouses. . of course you can buy the premium version if you like the app but it’s free to explore and use. No root or jail break required, easy to install, undetectable and hidden (no trace that it’s there), user friendly interface and whatnot.