Network speed testing apps won't count against T-Mobile customers' monthly data allowance
Besides the Speedtest.net app, other apps in the same vein will also not count against a customer's data cap. Part of the reason for T-Mobile to allow its subscribers to run these speed testing apps without being throttled, is because they allow the carrier to show off the speed of its network. In January, results from the Speedtest app revealed that T-Mobile had the fastest average 4G LTE speeds in the country. That was the same result that users of the Open Signal app came up with a few months later.
In addition, T-Mobile explained that it is not violating net neutrality rules since it is not treating the data from speed testing apps differently than the data from other apps. The carrier admitted that it just wants to show off the speed of its network to customers.