Lose Your Keys? Use Your Phone My quest to test an app called KeyMe started with five keys. KeyMe allows you to scan digital keys into the cloud with an iPhone, to be retrieved whenever one goes missing. Rather than waiting around for a locksmith to change the locks, or overpaying a landlord for a new set, you can take the digital specifications to any place that makes and sells keys. The app's creator, Greg Marsh, came up with the idea about two years ago, after several trying episodes involving locksmiths at his Lower East Side apartment. "The more I found out about keys and how they worked, the more it seemed like a digital storage program would work really well," he said. The KeyMe app gathers crucial information, including a key's type (SC1, for instance) and the height of and distance between the key's teeth. Any locksmith who has that information should be able to replicate your key. Of the five keys I tried to scan, two were normal-size cut keys, one for my apartment and the other for my parents" house. Another was the small key to my mailbox. The last two were more heavy duty: the keys to my bike lock and a black-jacketed Mul-T-Lock key to my apartment building. But KeyMe is unable to scan bike keys and "do not duplicate" security keys, bringing my virtual key ring down to three. And scanning those three was a struggle. KeyMe's scanning system requires the user to hold a phone completely still for about 15 seconds - a difficult prospect, particularly if you decide to scan keys after your morning coffee. Eventually though, the three keys that could be were scanned. After that, there were additional delays. None of the keys I had scanned made it to the key-ring display, which indicates that a key's specifications have been stored. Mr. Marsh explained that there was often a bit of a delay between scanning a key in and having its measurements available. "The last thing we want is to give someone a faulty key, so we've got strict thresholds about when a result is returned," he said. Two of the three keys that I had scanned in were added to my key ring after a couple of hours. But the tiny key to my mailbox didn't make it, probably because it was one of several key types that KeyMe has yet to support. With my two virtual keys, I strode proudly to my local locksmith. When I got there, I learned that to retrieve each key's measurements, I would have to pay a $9.99 fee to KeyMe, a cost that is not apparent when you download the free app. And that was in addition to the $10 my locksmith charged me for making a key from specifications (normal key copies are only $1.50; at the hardware store down the street, they're a quarter). I decided to have just one key made, to my apartment. It worked. From the five I had originally planned to scan, I ended up with only one $20 key. Anyone who had the foresight to scan keys with an app could have accomplished the same end merely by copying the keys at a hardware store for significantly less money. KeyMe is a good idea, but the app has quite a few doors to unlock before it becomes a viable alternative to simply being prepared. Have a favorite New York City app? Send us a tip by e-mail to appcity@nytimes.com or via Twitter to @Jonesieman.