ADT Inc. sells and supports monitored security and smart home solutions for U.S. households and small businesses, combining installed equipment with ongoing monitoring and related services. The company’s model is built around a large subscriber base (about 6.1 million monitoring subscribers as of December 31, 2025) served through nationwide sales and service offices, monitoring centers, and installation/service technicians. ADT is shifting from a traditional installed-and-monitored security provider toward a platform-centric approach anchored by its proprietary ADT+ application, aiming to unify professional installation and self-install options in one ecosystem. The ADT brand—associated with home security since 1874—remains central to customer acquisition in a trust- and reputation-driven category.