ProtonMail

ProtonMail is a free and open-source web-based encrypted email service founded in 2013 at the CERN research facility by Jason Stockman, Andy Yen and Wei Sun. ProtonMail is designed as a zero-knowledge system, using client-side encryption to protect emails and user data before they are sent to ProtonMail servers, in contrast to other common webmail services such as Gmail and Hotmail. ProtonMail is run by Proton Technologies AG, based in the Canton of Geneva, and its servers are located at two locations in Switzerland, outside of US and EU jurisdiction. The service received initial funding through a crowdfunding campaign and will be sustained long-term by multi-tiered pricing, although the default account setup is free. ProtonMail has approximately 500,000 users as of October 2015.