Two weeks ago, IP holding company Lodsys made waves by targeting small, independent iOS developers in a campaign to claim patent licensing fees for the use of in-app purchasing. That same company is now going after Android developers, citing the same dubious patent claims as the basis for requiring individual developers to pay for licensing of its patent.

Lodsys sent letters to at least a dozen iOS developers informing them that their use of Apple's in-app purchase APIs constituted infringement of its US Patent #7,222,078, "Methods and systems for gathering information from units of a commodity across a network." Lodsys claims this patent covers anything that might constitute an in-app upgrade button, and that Apple already licenses these patents, but the license does not extend to individual developers that implement in-app purchasing in their apps.

At least one Android developer has reported receiving a similar letter from Lodsys after adding support for in-app purchasing several weeks ago. The developer, going by the name "markusn82," posted the information to the "Android Discuss" Google Group.

Some developers believe the '078 patent is overly broad and could possibly be ruled invalid if any of the threatened developers took the case to trial. Further analysis suggests that even if the patent is valid, it does not apply to independent developers as Lodsys claims. However, none of the independent developers have the bankroll necessary to mount a lengthy and costly legal process to have the patent challenged in court.

Developers began campaigning for Apple to step in. The company's legal team sent a stern letter to Lodsys saying it should "cease its false assertions that the App Makers’ use of licensed Apple products and services in any way constitute infringement of any Lodsys patent." Apple said that its license to the patents—acquired in a deal with the previous patent owner Intellectual Ventures—extends to all its customers and business partners. In Apple's view, that expressly includes developers.

To cover all the bases, some iOS developers are attempting to pool resources to fight Lodsys if lawsuits do materialize.

Lodsys has claimed that both Microsoft and Google already have similar licenses to its portfolio of four patents, also acquired through deals with Intellectual Ventures. If Apple's analysis is correct, Android developers should be similarly covered by Google's license. However, even if Google were to send a similar letter to Lodsys warning it to stop threatening Android developers, that may not prevent Lodsys from following through on its threat to file patent infringement lawsuits.

Google did not respond to our request for comment on the matter before publication time.