But first it needs developers to make what consumers want.
The system will be based around a basic $50 skeleton with customizable modules
The company clarifies that emails are automatically scanned to provide users with tailored advertising and better search results
NTT DoCoMo, Modu and Microsoft have all showed modular concept phones, but Ara might be the most advanced yet.
New Mexico-based Titan's aircraft are designed to stay aloft for years and can provide voice and data services
The move, in early discussions, would add a layer of security for Web users.
But Google's modular smartphone architecture is at best a long shot, according to an analyst.
Even in beta, Microsoft's Cortana digital assistant has an impressive amount to say for itself. But is it enough to keep up?
A small number of people could see warnings with the new system, Google said.