Mailbox was a freeware email management application for iOS and Android, developed by Orchestra, Inc.

It drew the attention of numerous technology blogs for its usability and innovative features, such as swipe-based email sorting, snoozing and filtering.

[1][2] Weeks before its launch, a pre-registration period resulted in a waiting list of over 380,000 reservations.

For instance, it incentivized the user with visual cues and gestures to organize emails based on priority and due date to empty to inbox.

Mailbox's servers repeatedly queried the user's email account to provide push notifications and allowed the application to refresh its content without having to run in the background for prolonged periods.