Notification

A notification is a message that informs a user about an event, update, or action required. It can appear as a banner, pop-up, sound, badge, or message through various channels, and is delivered by software systems or human operators. The goal is timely awareness without requiring ongoing polling.

Types include push notifications delivered to devices via platform services; in-app notifications that appear within an application; desktop notifications; and non-interruptive channels such as emails, SMS, or calendar reminders. Common formats include banners, toasts, alerts, and badges.

Delivery mechanisms rely on event-driven systems and notification infrastructure. On mobile and desktop, operating systems provide notification centers and delivery services (for example, platform push notification services). Users typically opt in and can customize preferences, including do-not-disturb periods and quiet hours; privacy controls govern data collection and scope.

Design considerations include relevance, timeliness, and minimizing disruption. Best practices avoid excessive frequency, allow user control, support accessibility, offer succinct content, and provide actionable steps or links.

History and applications: early notifications appeared in computer systems as simple alerts; modern push notifications emerged with mobile platforms in the 2000s-2010s, enabling apps to alert users even when not in use. Today, notifications are integral to mobile apps, websites, operating systems, monitoring systems, and enterprise workflows.