Callfilter.app vs PhoneBlock

Callfilter.app is an Android app that blocks incoming calls according to rules set by the user. It can reject 8-digit numbers, numbers on a personal list, custom-pattern matches, or all incoming calls. Custom matching supports regular expressions, and users can choose to receive a notification when a call is rejected. CallFilter checks calls on the device through Android’s CallScreeningService API, using a local SQLite-based rule engine without remote database lookups. The maker describes it as offline, with no accounts or tracking. Its privacy policy says the app does not send personal data to external servers and does not use third-party SDKs, advertising networks, or tracking libraries. The app is free and open source, and the maker invites users to audit or contribute to the project on GitHub. It filters calls according to the user’s settings; it does not replace the phone app. The Play Store listing warns that some features may not work correctly on Samsung devices running Android 12 or later.

PhoneBlock is a free call-blocking service that uses a community-maintained database to identify unwanted advertising and spam calls. Users can report numbers through the app, website, or personal blacklist, and reports join the shared blacklist. The Android app blocks known spam calls, keeps call history, and supports reports and personal lists; it requires Android 10 or later. For incoming calls, the Android app sends only the phone number’s SHA-1 hash and does not access contacts.

Landline users can choose a router dongle, a Fritz!Box cloud answering machine, or a blocklist phonebook synchronized through CardDAV. The documented iPhone setup syncs spam numbers into contacts through CardDAV; a native iPhone app is in development, and beta registration is available. Phone systems can download the blocklist in different formats or query it through an API. PhoneBlock is licensed under GPL-3.0 and operated as a private project. The operator accepts email requests for help, including for mistakenly listed numbers. PhoneBlock costs nothing, with donations optional; its terms advise against business use.