YunoHost is an operating system aiming for the simplest administration of a server, and therefore democratize self-hosting, while making sure it stays reliable, secure, ethical and lightweight. It is a copylefted libre software project maintained exclusively by volunteers. Technically, it can be seen as a distribution based on Debian GNU/Linux and can be installed on many kinds of hardware. Features: (1) Based on Debian; (2) Administrate your server through a friendly web interface; (3) Deploy apps in just a few clicks from https://yunohost.org/#/apps ; (4) Manage users (based on LDAP); (5) Manage domain names; (6) Create and restore backups; (7) Connect to all apps simultaneously through the user portal (NGINX, SSOwat); (8) Includes a full e-mail stack (Postfix, Dovecot, Rspamd, DKIM)… as well as an instant messaging server (XMPP); (9) Manages SSL certificates (based on Let’s Encrypt)… and security systems (fail2ban, yunohost-firewall).