To spy on someone’s WhatsApp messages is possible only by using spyware. Any other service cannot provide such opportunity. Spyware works in the following way:
- It has to be compatible with a target device;
- A device must be prepared for the app’s installation (its official source explains on the subject);
- It has to be installed on the target device (the process is always described on official sources);
- It is subscription and package-based.
Examine the following spy apps to spy on someone’s WhatsApp messages: Spyera, iKeymonitor, SpyHuman, mSpy.