OnTimer is a calendar alarm app designed for iPhone users who need persistent, interruptive reminders for important events. Unlike standard calendar notifications that can be easily dismissed or ignored, OnTimer creates alarms that remain visible and require user action to dismiss, helping to prevent missed meetings, flights, appointments, and other critical moments. The tool addresses the common issue where users see a reminder but fail to act in time, often due to distractions or passive notifications disappearing before they prompt action.
The app connects to existing Google Calendar, Apple Calendar, or Outlook Calendar accounts, automatically turning upcoming events into alarms without requiring manual setup for each event. OnTimer supports multiple calendars, combining work and personal schedules in one place. It does not require users to rebuild their schedules, as it operates in a read-only mode, using the connected calendars as the source of truth for event information. When an event approaches, OnTimer triggers a loud, persistent alarm that stays on screen until actively dismissed, ensuring that the user is interrupted at the crucial moment to join, leave, or wrap up.
For events with a location, OnTimer offers "Time To Leave" alerts that factor in travel time and traffic, though this specific feature is mentioned as paid. The app also provides planning tools such as free time calculators to help users determine when to leave for flights, appointments, or other scheduled activities by working backward from the required arrival time. These calculators include tools for airport departures, cruise terminals, and wake-up times, aiming to reduce the risk of being late due to last-minute planning.
OnTimer is positioned as particularly useful for busy professionals, individuals with back-to-back meetings, people who often miss standard reminders, and those who experience time blindness or chronic lateness. The app is currently available for iPhone via the App Store, with an Android version in development and a waitlist open. Its focus on persistent, actionable alarms distinguishes it from traditional calendar notification systems.
OnTimer is a Productivity & Work product. It helps users avoid missing important events by turning calendar entries into persistent, hard-to-ignore alarms. It is built as a consumer product for busy professionals. There is a free tier. OnTimer is available on the web and iOS.
Ethan Garr builds and maintains OnTimer, and the product first shipped in 2026. PulseGate's similarity index finds few close equivalents — OnTimer occupies a relatively distinct niche. Key capabilities include persistent alarms, calendar integration, and Google Calendar sync.
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