PhoneBlock vs SpamBlocker

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.

SpamBlocker has no write-up on Specifiction yet; its figures are above.