Prefixer is an Android app developed by 253°Below (Att: Daniel Johansson Fjärde Bassängvägen 15 SE-115 83 Stockholm, Sweden).

Prefixer first became available on 26 Dec 2011. It is estimated that Prefixer has been downloaded between 100000 and 500000 times from the Play Store.

Prefixer 2.1 requires the following permissions:

Allows applications to access information about networks.

Allows applications to access information about Wi-Fi networks.

Allows applications to connect to paired bluetooth devices.

Allows applications to discover and pair bluetooth devices.

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

Allows access to the list of accounts in the Accounts Service.

Allows an application to modify global audio settings.

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 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 access to the vibrator.

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.