How many phones does it take to test out the Facebook app? Almost 2,000. The number is no joke and not even a rough estimate. In Facebook’s Mobile Device Lab, dozens of server racks are lined on each side humming to the point where it feels more like an airport hanger rather than a cool, dark room.

Some of the server racks hold smartphones, of varying models and varying ages. Each rack can snuggly fit 32 devices, and each of them is on Facebook 24/7. Facebook’s Mobile Device Lab manages the phones in order to test the apps’ performance before each update.

Within The Racks Of The Mobile Device Lab

The devices run different versions of the Facebook app, Facebook Lite, Messenger, Instagram, and so on, but all of the devices have automated gesture programs running on them, which makes the phone behave as it was actually used by a human being. Likes, comments, stickers, tagging, searching, surveys, the gesture programs do them all, while monitoring chip, memory, and battery usage.

Small cameras hang above the screen of each phone recording every second of uptime so that engineers and researchers can see exactly what crashes when so that they can fix it.

So why does a Facebook’s Mobile Device Lab need almost 2,000 different devices? Well, because they are different. The smartphone market is a very big place. While most of us know the bigger names that pop up every year, there are actually hundreds of different smartphone manufacturers.

Almost each brand has a different chip covering the CPU, GPU, and modem, potentially different RAM and internal storage manufacturers, as well as different battery manufacturers and limitations. And each brand releases on average one or two phones per year.

The Mobile Device Lab needs to account for all the tech specs of a device. The apps need to look good and behave, no matter what device they run on. Phones with different or unique screen sizes, for example, also require their own version of Facebook.

Then there is the issue of operating systems, as almost each version of Android has its own settings and most phones also come with their own modified version of Android.

App developers are well aware of the fact that an app can work perfectly on several models of phones but crash on others, even if they’re running the exact same OS.

iOS devices run the same version, which is great for app developers, but technical specifications such as CPU, GPU, memory, and screen size are still an important factor.

So the next time the Facebook app glitches out, we can think of the Mobile Device Lab and know that they sometimes have their hands full but that they will eventually get to it.

Photograph Courtesy of Flickr.