Even after closing the apps, some of them always keep running in the background – consuming your device’s CPU power as well as hogging the already limited RAM. This not only makes other apps slow to respond but the whole Android a little bit sluggish. You can see the difference by running AnTuTu benchmark on a device that you have just powered on or restarted and on the same device after it has been running for many days. One way to stop these running apps is to use the Zapper Task Killer which kills these apps in a matter of seconds, freeing up the RAM and improving the overall performance of your device.
The Zapper Task Killer is designed by the smart folks at Lookup Security who also make the Lookup Antivirus apps for Android. As you launch this app, it shows you a list of all the apps running on your system. For each of the apps, it shows the memory consumed, the number of processes and the number of services being run. It also shows a zapper icon (looks like lightning or power icon) or a gear like icon. If you see a zapper icon against an app in the list then that app can be zapped (killed). On the other hand, if you see a gear like icon, then that app cannot be killed by Zapper.
You can go ahead and select the apps that you want to kill. You can tap on Select All on the top to select all the apps. Then a single tap on Kill Apps will terminate the selected apps. You will hear a sound that as if someone has fired a gun equipped with silencer – that is Zapper killing the apps.
In case you want to terminate the apps that Zapper marks with a gear like icon, you will have to proceed manually. You can tap on the gear like icon against an app that you want to kill, it will show you a warning and then take you to the Android app settings where you can tap on Force stop button to kill that app.
Conclusion: Zapper Task Killer is a lightweight, fast and easy-to-use task killer app for Android. It kills the selected tasks very fast and avoids killing of the tasks that can make the system unstable.
You can get Zapper Task Killer from https://play.google.com/store/apps/details?id=com.lookout.zapper.
Update February 2018: Unfortunately, Lookout Security has discontinued this app. You can find the APK from some places on the internet, but it is not recommended. You can find alternatives like 1 Tap Task Killer.