cal.com

Cal.com: The better way to schedule your meetings, offering a fully customizable experience for individuals and businesses.

Threema Broadcast

Threema Broadcast is a secure web application for efficient one-to-many communication via instant messaging, offering features like messenger newsletters, chatbots, and centrally managed groups.

WinSCP

WinSCP is a free and Open Source SFTP client for Windows that provides a secure and user-friendly way to transfer files between a local computer and remote servers.