Letterboxx - A reader for email newsletters.

Letterboxx is a premium macOS application designed specifically for reading and organizing email newsletters outside of your inbox. Instead of treating newsletters like ordinary email, Letterboxx imports copies from the email accounts and folders you choose, creating a beautiful local library where your favorite publications are easy to browse, search, and revisit. Whether you subscribe to technology news, research, essays, shopping deals, local news, or niche publications, Letterboxx provides a dedicated space that feels more like a personal library than an email client. The app includes powerful organization tools such as custom Letterboxes, automatic sorting rules, favorites, reminders, highlights, quick filters, and full-text search to help you manage large newsletter collections effortlessly. Clean View removes advertising, tracking elements, and unnecessary clutter to create a focused reading experience, while built-in unsubscribe detection makes managing subscriptions easier. Unlike traditional email clients, Letterboxx does not support composing, replying, or forwarding messages—instead, it focuses entirely on helping users enjoy the newsletters they intentionally subscribed to. Privacy is central to the experience: your newsletter library is stored locally on your Mac, without ads, social features, or data selling. With native macOS design, keyboard shortcuts, multiple themes, backup and restore capabilities, and seamless integration with Gmail, Outlook, and IMAP accounts, Letterboxx offers a calm, distraction-free home for your newsletters while allowing you to continue using your preferred email client for everyday communication.