Dave Girouard, vice president of product management for Google Apps has quit to launch his own company called UpStart.

Girouard, who has been working at Google for eight years, is widely known for developing Google Docs, is considered a serious MS-Office Killer app. Other than Google Docs, Girouard is the man behind Gmail, Google Calendar and other numerous cloud applications.

Google says he is parting on amicable terms, and Google Ventures is backing UpStart along with Perkins and NEA.

In a post on his Google+ page, Girouard thanked Google CEO Larry Page, former CEO Eric Schmidt and Google’s co-founder Sergey Brin.

“It's true. After eight wonderful and life-altering years, I've decided to leave Google to pursue my own adventure. I owe a lifetime of gratitude to +Larry Page +Sergey Brin and +Eric Schmidt and so many others at Google for giving me such an incredible opportunity. I don't know if I'll ever match the learning experience I've had here, but I'm going to give it one hell of a try!” Girouard wrote.

According to its home page, UpStart lets investors raise capital in return for a small portion of future income.

“In recent months, I've thought a lot about the younger generation; about the opportunities and challenges they face in navigating their careers and life choices. The result is www.upstart.com, which you'll (hopefully) hear a lot more about in the coming months,” Girouard wrote. The company is aimed at funding people, instead of companies. Initially, interest rates will be kept extremely low to attract customers.

The leader of the Chrome and apps team, Sunder Pichai, will take on Girouard’s duties at Google.

(reported by Johnny Wills, edited by Wendy Li)