CTemplar is described as 'Security and privacy focused email provider based in Iceland. They use E2EE to keep your conversations private and secure. Their service offers onion address for those who want the best possible privacy and security' and is an app in the security & privacy category. There are more than 10 alternatives to CTemplar for a variety of platforms, including Web-based, Android, iPhone, iPad and Mac apps. The best CTemplar alternative is Proton Mail, which is both free and Open Source. Other great apps like CTemplar are Gmail, Tuta Mail, Disroot and Zoho Mail.