One sign that the iPhone development world is starting to mature is that companies are beginning to build the infrastructure necessary for devs to enable push notification and in-app purchasing. Usually these functions require a developer to make a significant investment in server hardware and labor to set up and operate the push and/or purchase servers, as well as to write code to integrate those services into their apps.

I met with Tim Courtney and Chris Grove of KeyLimeTie yesterday at 360iDev in downtown Denver. Their company's new service, iLime, is a scalable solution consisting of highly reliable server infrastructure and a set of iPhone Application Programming Interfaces (APIs) that make it possible for iPhone developers to integrate Apple Push Notification Service (APNS) and in-app purchase easily.

iLime is making it very easy for small, independent developers to test the waters of push notification by making their APIs and server prowess available for free for up to the first 25,000 push messages each month. After that point, the service is charged on a per-push basis on a tiered pricing structure that makes higher volume more attractive. For in-app purchasing, iLime simply charges a flat US$0.05 fee for every content purchase made through their service.

iLime was first announced at iPhone Dev Camp in August. At 360iDev, iLime announced additional features and detailed documentation of the APIs. Courtney also noted that while there are only a handful of apps in the App Store at this time using iLime's services, several hundred iPhone developers have tested and used the services and they expect a significant number of iLime-enabled apps in the near future.

It's great to see KeyLimeTie making the investment in the virtual bricks and mortar that enable push notification and in-app purchasing, so more iPhone devs can take advantage of these iPhone OS features.