The web-based email service is based on open-source code. Credit: Al Sacco Mozilla has decided to launch a challenger to Gmail called Thundermail. The upstart is a web-based email service based on the open-source project Stalwart, according to technology site Thurrott. The plan is to eventually add support for calendar and contacts to Thundermail, but when that would happen remains to be seen. Alongside the new email service, Mozilla is also launching Thunderbird Pro. It offers, among other things, an AI assistant, a file-sharing tool and a planning tool and can be seen as a complement to Thundermail. Users interested in trying the new services, can sign up for a waiting list at Thundermail.com. SUBSCRIBE TO OUR NEWSLETTER From our editors straight to your inbox Get started by entering your email address below. Please enter a valid email address Subscribe