In a play for the payments business of PayPal and others, Google officially opened its In-App Payments product to developers this week.

Google told developers on Wednesday that they were free to hit the In-App Payments sandbox to start developing. Opening the sandbox is an important first step toward full deployment.

Google said it is “preparing In-App Payments for a full launch this summer.”

Developers can find the sandbox here.

SCREENSHOT OF GOOGLE’S IN-APP PAYMENTS WEBSITE