PhoneBlock vs RoboKiller

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.

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.