Postbox is an email application. Postbox has ultra fast search system with that users can find messages, attachments, links, and contacts. Conversation Postbox is integrated with the Address Book, iCal, iPhoto, Spotlight, and Quick Love. Postbox organizes your all email accounts in one place. It is compatible with macOS + Windows. Postbox also has the feature for Dark mode, It will automatically adapt to the light and Dark Mode preferences you set in the OS.