1. User Interface: Roundcube is mainly an email client, offering a user-friendly web interface for users to access and manage their email accounts easily. On the other hand, phpList is a service focused on email marketing and newsletter campaigns, providing tools for managing subscriber lists, creating email campaigns, and tracking campaign performance.
2. Primary Functionality: Roundcube is designed for personal or business email communication, providing features such as email composing, sending, receiving, organizing emails into folders, and configuring email settings. phpList, on the other hand, is specialized in managing mailing lists, sending bulk emails, analyzing campaign metrics, and integrating with other systems for efficient email marketing operations.
3. Customization Options: Roundcube offers limited customization options in terms of appearance and functionality, primarily focusing on email-related features. In contrast, phpList provides extensive customization capabilities, allowing users to design and tailor email campaigns according to their branding and targeting requirements.
4. Subscription Management: One of the key differences between Roundcube and phpList is the handling of subscriptions. Roundcube does not have built-in features for managing mailing lists or subscriber databases, whereas phpList is specifically designed to handle subscriptions, unsubscribes, and managing large volumes of email recipients efficiently.
5. Automation and Campaign Tracking: phpList excels in automation features such as scheduled campaign sending, autoresponders, and advanced campaign tracking metrics like open rates, click-through rates, and subscriber engagement statistics. Roundcube, on the other hand, focuses on the core email functionality without advanced automation capabilities.
6. Integration with Third-Party Services: phpList offers extensive integration options with third-party services and tools for enhanced functionality and efficiency in email marketing campaigns. In comparison, Roundcube is more standalone and may require additional plugins or extensions for integrating with external services.

In Summary, Roundcube is an email client focused on personal/business communication, while phpList is an email marketing platform with subscription management, customization, automation, and integration features.