The Empty Housing Hotline is a website published by Mokum Kraakt for people to submit information they have about empty buildings in Amsterdam. Users can chose to stay anonymous and upload any material they might have collected. All submissions are encrypted, kept safe on a server somewhere in Iceland, and only shared with friends, so as to not alarm owners.

The long term goal is to open source the code, to make it possible for collectives in other places to set up similar systems.