Roundcube
Roundcube is a free, open-source webmail client written in PHP that provides a browser-based interface for accessing email accounts via IMAP and SMTP protocols. It offers a user-friendly, desktop-like experience with features such as drag-and-drop, address book management, and MIME support for attachments. It is commonly used as a self-hosted email solution for organizations or individuals seeking privacy and control over their email data.
Developers should learn or use Roundcube when building or maintaining self-hosted email systems, particularly for small to medium-sized businesses, educational institutions, or privacy-focused projects that require a customizable and secure webmail interface. It is ideal for scenarios where integration with existing IMAP/SMTP servers (like Postfix or Dovecot) is needed, and when avoiding proprietary email services (e.g., Gmail or Outlook) is a priority. Its extensibility via plugins makes it suitable for adding custom features or integrating with other web applications.