protocol and by creating free Google accounts. The remaining constraint was time, as Google also enforces a strict account-level rate-limit: a given account is not allowed to download more than a certain number of apps in a given time frame. Google Play has several features that make automatic crawling harder than other markets. As a result, a more elaborated crawler is required for this market. Google further enforces limits on the number of apps that can be downloaded per Google account in a given period from one IP address. To overcome those limits, we wrote a software dedicated to finding and downloading apps from Google Play. This software is built with two components: a central dispatcher, and a download agent. We have used agents on up to seven machines located in Luxembourg, France and Canada. On three of these machines, we ran two instances of the agent, one using exclusively IPv4 connectivity and the other using IPv6. Because IPv4 and IPv6 addresses are not linked in any way, this allows to hiding the fact that those two agents run on the same machine, hence enabling us to increase the number of apps downloaded from one computer without increasing the risk 