Amazon is moving to build an ecosystem for Alexa, the voice service that is the brain of Echo, via a software developer kit, third party hardware vendor hooks and a $100 million investment fund.

The blitz comes just a few days after Amazon opened Echo sales up to the masses. Echo has generated a good bit of buzz and has piqued developer interest. "Since introducing Amazon Echo, we've heard from developers, manufacturers, and start-ups of all sizes who want to innovate with this new technology," said Amazon CEO Jeff Bezos.

The software developer kit (SDK) is called the Alexa Skills Kit, which is a series of application programming interfaces that allow developers to create voice features for Alexa.

Previously: Amazon Echo now available to anyone for $179.99 | A dozen helpful Amazon Echo how-to tips and tricks | Amazon Echo review: A perfect 10 | Amazon Echo: Five months in, it's the most used gadget in my home | How Echo is slowly, quietly becoming your smarthome hub

The aim for Amazon is to enable developers to integrate Alexa into their applications or create new services. The SDK for Alexa will have a developer preview that starts Thursday. Intuit, StubHub, AOL and Citrix are some of the early companies using the Alexa Skills Kit.

Here's the flow of Alexa services as outlined in Amazon's getting started guide.

On the hardware front, Amazon said that it will open Alexa's voice services up to third party hardware makers. Amazon will allow hardware vendors to use the Alexa Voice Service for free.

The goal on both hardware and developer fronts is to integrate Alexa into a bevy of devices.

Amazon is also throwing money into the Alexa ecosystem with a $100 million investment fund. The fund will be used to finance developers, manufacturers and start-ups that use Alexa for services.

The Alexa Fund has seven investments at launch including Orange Chef, a mobile app connecting kitchen tools; Scout Alarm, a home security provider; Garageio, a garage door monitoring service; Toymail, a connected toy specialist; Dragon Innovation, a garage to factory framework; MARA, a voice based running assistant; and Mojio, a connected car company.