When Google announced its Home speaker to take on the Amazon Echo, I made a big assumption: it was essentially a super-powered Chromecast device at its tiny little heart. Making assumptions is a stupid thing for a tech reporter to do, but turns out this one was accurate. Amir Efrati at The Information has confirmed from "a person with direct knowledge of the plan" that Google Home will be based on the Chromecast.
It's not a surprise at all: Chromecast and the Cast standard it uses are both one of the rare hardware success stories in Google's recent history. It also makes sense because of what Google Home is mostly meant to do: grab information off the internet and tell it to you in a conversational way. Sending and receiving bits of information from the cloud is literally what Chromecast was built to do. One thing Chromecast isn't good at, though, is apps. They all need to be in the cloud and they need to be able to communicate with Google in order to work with Google Home. At Google IO earlier this month, the company told me it was taking a slow and steady approach to creating that third-party ecosystem. As often seems to be the case with assistants, partnerships tend to win.
There's a universe where the Google Home could have been built on Android — that would allow it to do more computation locally and also change the equation for third party app developers. In fact, Efrati's source says that very idea has been "discussed" within Google. But Android in the living room has had a really difficult time in essentially every instantiation that Google has tried so far, so it makes sense that to get Home to market (relatively) quickly, Google would opt for the simpler and more direct solution: Chromecast.
As for a release date or price, we still don't have anything firm beyond later this year for an as-yet undisclosed price.