Call Filter is an Android app developed by telemarks.co.jp (〒１１３－００３３　東京都文京区本郷３－２－２リベールお茶の水渡邊ビル３Ｆ). Others apps created by telemarks.co.jp are: Battery Meter & Saver, 2ndHOME, App Defender, Android FlashLight.

Call Filter first became available on 03 Apr 2016. It is estimated that Call Filter has been downloaded between 1000000 and 5000000 times from the Play Store.

Call Filter 4.1.1 requires the following permissions:

Allows applications to access information about networks.

Allows an application to initiate a phone call without going through the Dialer user interface for the user to confirm the call.

Allows an application to call any phone number, including emergency numbers, without going through the Dialer user interface for the user to confirm the call being placed.

Allows applications to open network sockets.

Allows an application to call killBackgroundProcesses(String).

Allows modification of the telephony state - power on, mmi, etc. Does not include placing calls.

Allows an application to see the number being dialed during an outgoing call with the option to redirect the call to a different number or abort the call altogether.

Allows an application to read the user's call log.

Allows an application to read the user's contacts data.

Allows an application to read from external storage.

Allows read only access to phone state, including the phone number of the device, current cellular network information, the status of any ongoing calls, and a list of any PhoneAccounts registered on the device.

Allows an application to read SMS messages.

Allows an application to receive SMS messages.

Allows an application to send SMS messages.

Allows an app to create windows using the type TYPE_SYSTEM_ALERT, shown on top of all other apps. Very few apps should use this permission; these windows are intended for system-level interaction with the user.

Allows an application to write (but not read) the user's call log data.

Allows an application to write the user's contacts data.

Allows an application to write to external storage.