ohsevin/cryptpad

CryptPad is an end-to-end encrypted, open-source collaboration suite that enables real-time document editing and synchronization while keeping content private from server administrators. It's designed for individuals and teams seeking secure, private collaboration tools, with features like encrypted rich text documents, spreadsheets, and presentations. The project is actively maintained by XWiki SAS and supported by grants and community contributions, making it ideal for privacy-conscious users and organizations.