Psiphon is a proxy and VPN service designed to circumvent internet censorship. The first version of Psiphon was developed at the University of Toronto's Citizen Lab. This initial version allowed users in countries that do not censor the internet to provide proxy services for their friends in countries where the internet is censored. In 2007, Psiphon, Inc was founded as a Canadian company separate from the Citizen Lab. In current versions of Psiphon, connections are routed through Psiphon Inc's globally distributed cloud-based network of proxy servers. This network uses a performance-focused single hop architecture. The Psiphon FAQ notes that this design focused on circumventing censorship, but it does not provide strong anonymity - users that require anonymity should consider Tor instead. Psiphon has been used to circumvent large-scale government censorship of the internet a number of times in the recent past: in 2015 and 2016 when the Brazilian government blocked WhatsApp; in 2016 when the Moroccan government blocked VoIP services; and in 2016 when the Ugandan government blocked Facebook, Twitter, WhatsApp, and Mobile Money. Psiphon is open-source software under the GNU General Public License, with source code available on GitHub. Psiphon clients are available for Windows, iOS, and Android.