A shot of Clapfoot&39's Tank Hero game, which is being targeted for allegedly infringing on another company&39's patents by including in-app purchase, a feature Google provides.

Lodsys, the company that's gone after a number of Apple iOS developers for allegedly infringing on its patents, is now doing the same to at least one developer on Google's Android platform.

Cult of Mac has dug up a developing discussion thread on Google's Android developer forums, noting that at least one Android developer has been targeted by the group over the use of in-app purchase within their application.

"We recently implemented in-app purchases for our Android application and several weeks later we received a letter from Lodsys, claiming that we infringed on their patents," wrote the developer of Tank Hero, a game on the Android Market. "We are obviously a small shop and are not financially capable of defending ourselves over a litigation."

Lodsys began targeting iOS developers earlier this month for infringing on four of its patents by including in-app purchase functionality within their apps. In-app purchase is a feature Apple offers as part of its software development kit, and requires developers to use if they want to provide paid add-ons to their games and applications.

Apple responded earlier this week by sending Lodsys, along with affected developers, a letter saying that Apple's own license with the company over the patents covers developers and their applications. Furthermore, Apple said the group's argument was weakened by the fact that its in-app purchase mechanism required several of Apple's own technologies.

Google added an in-app billing option to Android Market apps at the tail end of March. It was pitched as a way for developers to sell virtual items, including levels or additional features. By comparison, Apple launched its in-app purchase solution in 2009. Those dates are particularly important based on the fact that Lodsys has mentioned in its letters that it can seek past revenues from in-app purchases made within infringing apps as part of a licensing deal.

Google and Lodsys did not immediately respond to a request for comment. Lodsys previously stated that it will not talk to press, and plans to only communicates through its own blog.