Callfilter.app

What Callfilter.app is

Callfilter.app is a free, open-source Android app that rejects incoming calls according to rules you choose. It can block 8-digit numbers, numbers on a personal list, custom-pattern matches or all incoming calls. Custom rules can use regular expressions to match phone numbers, and the app can optionally notify you when it rejects a call. Call checks run locally through Android’s CallScreeningService API, using a SQLite-based rule engine without remote database lookups. The maker describes the app as offline, with no accounts or tracking. Its privacy policy says the app does not collect, store or transmit personal data to external servers, and does not use third-party SDKs, advertising networks or tracking libraries. CallFilter only filters incoming calls based on your settings; it does not replace the phone app. The maker invites users to audit and contribute to the open-source project on GitHub. A device-specific caveat is that some features may not work correctly on Samsung devices running Android 12 or later. Support is available by email.