Cross-posted from the Google Checkout Blog

By Amit Fulay, Product Manager and Mikhail Seregine, Software Engineer

Today at Google I/O, we launched the developer API of Google In-App Payments for the web. In-App Payments enables any web application to receive payments from users and keep them engaged in your application. It is available to all US developers in sandbox today and will be followed by a consumer launch and an international rollout over the summer.

The team started building Google In-App Payments soon after Jambool was acquired by Google in August 2010. This project brought Social Gold technology and expertise and combined it with Google scale. For the payments platform that we’re announcing today, the theme is simplicity:

The simple API makes integration fast so you can start getting paid sooner. Implementing In-App Payments requires only two API calls: one to initiate the payment, and one to accept the notification when a payment is made.

The simple user experience will let your users pay without leaving the app or entering billing details. Users who have previously completed a purchase on Google Checkout, Android MarketGoogle eBookstore, YouTube Movies and more can use that same account to pay for items in your app in minimal steps. Fast payments that keep users in your game or site can boost customer conversion rates, increasing your revenue.

The simple pricing model is a flat payment processing fee of 5%. It’s 5% whether you distribute your app yourself or via the Chrome Web Store. There are no fixed purchase fees, setup costs, or monthly minimums.

The JavaScript version of the In-App Payments API is available to developers today. A Flash version of the API will be available in the coming weeks.

We invite you to sign up, start integrating your apps and send us feedback. Let’s work together to delight consumers this summer with amazing web apps, monetized effectively, all in the app.