Amazon has announced the launch of a new in-app purchase service, which allows users to make purchases inside the apps, for all apps offered though it App store.

The service allows developers to let users spend money inside of apps, which may have been downloaded for free or for some price. The service will add a new way for developers on the platform to generate revenues by selling in-app features and attributes to the users.

The new service could bring Amazon in the direct line of fire from an aggressive patent-holding firm named Lodsys. Lodsys, a company based in Texas that claims of owning a number of patented technologies, claims that it owns patents on the method used to offer features within an app.

Lodsys had sued several large and small developers claiming damages for patent infringement. It had sent letter to iOS developers threatening them with legal actions if they did not enter into deals with the company.

Even as Google, Apple, and Microsoft have obtained licenses from the company for using the technology but Lodsys claim that these licenses do not cover app developers and they are required to obtain licenses separately.

Apple's legal department had written a letter to Lodsys and its CEO Mark Small saying its existing license for patents covering in-app purchases indeed covers all iOS app makers. The letter also indicated that Apple is entitled to share the technology with third party developers, as it already has and it s ready to defend its license rights.