On Monday Fortumo, the company probably best known for its in-app purchasing provider for Android developers, released an API for cross platform HTML5-supported mobile payments. This will allow app and game developers to easily integrate in-app payments for any mobile HTML5 based application. The service allows billing to customers’ phone bills, which can open up a whole range of new customers who don’t have credit cards.

“Mobile web apps are interesting for developers because they are platform-independent,” says Martin Koppel, CRO of Fortumo in a press release. “We’re looking to provide web app developers with similar mobile payment tools that native app developers have.”

The Estonia/California based company has carrier billing partnerships in 60 countries with 230 carriers. The flexibility and international reach of Fortumo’s HTML5 payment service will likely enable new was for developers to monetize apps, especially in emerging markets. Mobile Operator Billing allows a payment to go to a user’s phone bill, and does not require a credit card.

Fortumo’s HTML5 mobile billing API is available to any merchant, free of charge, on the company’s webpage.