Unknown Call Blocker

Unknown Call Blocker helps reduce interruptions from unsaved numbers. After you grant the required permissions and select the app for caller ID and spam screening, calls from your contacts continue to ring. For numbers outside your contacts, you can choose to reject or silence calls.

Call blocking turns on automatically when you finish initial setup with contacts access, the caller ID and spam role, and the battery optimization exemption granted. You can turn it on or off from the home screen.

Features:

- Optional Smart Delay allows callbacks from outgoing numbers observed after activation, within the default 30-minute window. Activation requires accepting the data-use disclosure.
- Optional bypass for a second call from the same number within five minutes.
- Local history of blocked or silenced calls, with tap-to-copy phone numbers, statistics, and CSV export of those records.
- Alerts about permissions and settings that may affect protection.
- PIN lock and biometric unlock, when supported.
- Optional Community Protection that sends blocked numbers and a random installation identifier to help build a shared spam list.

Smart Delay records remain on this device and are not sent to Community Protection, exported or included in backup. They are deleted when the feature is disabled and invalidated after a device reboot. Calls made before activation or while another app holds the caller ID and spam role cannot be recovered. Personal call history and contact names are not sent to Community Protection. Call blocking depends on granted permissions and Android settings. Requires Android 10 or later. The app does not block messages or silence message notifications.