Callfilter.app vs RoboKiller

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.

RoboKiller is an Android and iOS app that blocks spam calls and filters spam texts. Its call-blocking algorithm analyzes call metadata in less than a millisecond and blocks calls it identifies as spam before they reach the phone. Audio fingerprinting compares robocall recordings against a database of more than 1.5 billion processed phone numbers and millions of audio fingerprints. RoboKiller says its technology is 99% effective at stopping spam calls. Text filtering uses block and allow lists, number reputation, and content analysis; the company says messages are never stored or shared. The free version includes a daily-updated blacklist, blocked-call notifications, weekly insights, spam reporting, and Spam Patrol. Answer Bots, Call Screening, and Personal Data Protection require a paid plan. Answer Bots play prerecorded messages to spam callers, while Call Screening asks unknown callers for their name and reason for calling. Both features require a carrier and plan that support Conditional Call Forwarding. Listed paid options include $4.99 a month, $31.99 a year, and $39.99 a year; a 7-day trial is also listed.