Call Blocker

What Call Blocker is

Call Blocker is a free Android application for stopping unwanted calls. It can block individual numbers, numbers matching a prefix, and private numbers. Blocking rules can be configured separately for each SIM card, supporting phones with dual SIMs. The app keeps a history of blocked calls and provides call screening. Complete backup and restore are supported, with backups saved either as readable JSON or encrypted .cbbk files using AES-256-GCM. The project warns that unencrypted JSON backups remain readable. Its documented permissions cover phone state, call logs, answering calls, notifications, and call screening, with stated uses. The interface is available in Spanish and English and forces a dark theme. The maker states compatibility with Android 9 through Android 17 (API 28+). Call Blocker is licensed under GNU General Public License v3.0. Blocked-call notifications are listed as unfinished, and the project is pending review for inclusion in F-Droid.

Who it suits

It suits Android users who need number, prefix, private-number, or per-SIM blocking rules. It also fits users who want backup and restore options with optional encryption.

Limits

The maker lists compatibility with Android 9 through 17 (API 28+). Blocked-call notifications are not yet implemented, and readable JSON backups do not provide encryption.

Getting started

1. Open the project website on an Android device
2. Install Call Blocker for Android 9–17
3. Grant the listed phone, call-log, answering, notification, and call-screening permissions
4. Configure number, prefix, private-number, or SIM-specific blocking rules
5. Create an optional JSON or encrypted .cbbk backup

Verdict

Call Blocker provides focused call screening and flexible blocking rules on Android, including dual-SIM configurations. Backup choices are broad, but notification support is unfinished and readable JSON requires care.