Mailfence is a secure email service provider focused on protecting user privacy. It offers end-to-end encryption, digital signatures, and access to open-source security tools. It is designed to provide a secure, private, and ad-free email experience. It also provides tools to manage contacts, shared documents, calendars, and tasks. It is accessible from any device, with its mobile version available for Android and iOS. Mailfence is compliant with GDPR and ISO 27001. It also offers two-factor authentication, IP address blocking, and password protection for emails. Additionally, Mailfence offers secure file storage and sharing, anonymous email forwarding, and a secure VPN.
Protonmail is a closed platform, and has no similarity to Mailfence (except in the sense that both use OpenPGP as their end-to-end encryption technology).