Nothing in Heym signalled that a task was about to start. Staying on time meant keeping the tab in view or setting an alarm elsewhere.

Tasks and habits now have reminders. Each one arrives as a system notification while Heym is open in a browser tab, background tabs included, or in the desktop app for macOS. A task's notification shows its name and "Starts at 2:00 PM" or "Due today", and clicking it opens the task.

In a task's details, Reminders sits under Labels. Click it and type "30m", "2h", "1w" or "2pm"; a plain "2" offers 2 minutes, 2 hours, 2 days or 2 weeks before. Relative reminders count back from the start time, and a clock time becomes "On the day at 2:00 PM", which also works for all-day tasks. A task holds up to 10. The bell button opens the same field when adding a task, and typing "Call mom !2pm" in a task's name moves "!2pm" into a reminder.

Habits get the same Reminders field, below Schedule. It fires on every scheduled day until that day is done; partial progress doesn't count. Skip or Fail silences it for the day. A habit with a weekly target, such as 3× / week, reminds daily until it's met, then stays quiet until next week. Set reminders… under Actions gives a selection of tasks or habits the same reminder.

Heym adds a default reminder when a task with no reminders gets a date or start time, and to every new habit. Out of the box that's 5 minutes before with a start time and 9:00 AM on the day without one. Habits created before this release start with none. Both defaults, and separate switches for task and habit notifications in each browser, are in Settings → Notifications.