New tool helps mistreated tenants demystify building ownership uses an algorithm built on NYC open data to map property ownership across the city.

News Story (New York)

Zoe Rosenberg
December 5, 2018

Tags: Housing: Landlord-Tenant, Technology

Organizations mentioned/involved:,


The tool, called, primarily uses data from the Department of Housing Preservation and Development’s multiple dwelling registrations to show users the business entities, business addresses, and people associated with the property. also shows users the property’s number of total and open violations as well as the eviction rate for the building in the previous year.

The tool cuts through the opaque layers of building ownership in New York—think limited liability corporations—and helps tenants get the information they need to either hold their landlord accountable or collectively organize with other tenants suffering the same abuses across buildings.