Last September, Nest announced their Nest Developer Program. In preparation for tomorrow’s Google I/O conference, the Nest Developer Program is now active.

If you watch the video embedded below, you’ll get a sense of Nest’s vision for the home. Clearly, this is in direct competition with Apple’s HomeKit, part of an already crowded smart home space.

Startups like SmartThings and Revolv sell smart hubs, usually for around a couple hundred dollars, that act as wireless command centers for Internet-connected gadgets around the home, like light bulbs, wall switches and motion sensors.

New York-based Quirky has partnered with General Electric on a brand-new, smart-home focused arm called Wink. Honeywell, which in 2012 filed a patent-infringement lawsuit against Nest Labs, recently released a Wi-Fi-connected thermostat called the Lyric that has a sleek new design and promises convenience and energy savings.

Perhaps the biggest elephant in the room is Apple, which announced plans for a home automation software kit during its developers conference in early June.

Apple started its pursuit of developers at WWDC a few weeks ago. Presumably, Google will do the same at Google I/O, starting tomorrow. Though the space is, indeed, crowded, Apple and Google have the largest developer communities of any other players.

Seems logical that Samsung will covet this market. Not sure how they’ll get there, though. They can copy and create, as they did in the phone and tablet space, but they rode on the Android coattails for developers, for apps. Not clear they’ll be able to do that in this case, given their commitment to the Tizen OS.

Microsoft also has a large developer community and has long pursued the smart home holy grail with their HomeOS.

The players are all lining up and the home automation space seems ripe for evolution. Going to be interesting to watch this all play out.