The feature that allows you to see when someone was last online on WhatsApp can also be used for spying, among other things.
For the most part, the possibility of seeing when some of your friends were last online on WhatsApp is very useful. But in some cases, this feature can also be used for not so honest stuff, such as spying.
ChatWatch, an app available for Android and iOs, uses public information about when your friends are online and offline to show you when they are using WhatsApp.
With the help of the ChatWatch app you can tell which is the sleep pattern of your friends or you can even hint if two people are chatting with each other on WhatsApp, based on the times they are online.
Even if the “last seen” feature is disabled, the ChatWatch app can tell when someone is using WhatsApp. A small downside is that the app needs approximately 24 hours before it can show you relevant information regarding your friends Whatsapp usage patterns.
If you’re spying on two contacts, the app can correlate the information from each one and can show you when they synced online. This way you can tell if two of your friends talked to each other especially at hours when people are usually sleeping.
For the time being the ChatWatch app has disappeared from the App Store but you can stil download it from the Google Play Store for Android. You need to know that the app is not free and you will need to pay $2 per week. But this is a small price to pay to spy on your friends, right ?