Native macOS app

DayMerge

Reminders and To Do, one daily view.

If your tasks are split between Apple Reminders and Microsoft To Do, neither app shows you the whole day. DayMerge reads from both, merges them into one unified list, removes the duplicates that come from syncing the same task twice, and groups everything by day into a combined journal-and-calendar view — so "what's on today" is a single screen.

What it does

Two sources, one list — pulls tasks from Apple Reminders (EventKit) and Microsoft To Do (Graph API).
De-duplicates tasks that appear in both places.
Day view — groups tasks by date into a journal/calendar layout.

Status: Built — the merge, de-duplicate, and grouping core is complete and unit-tested, and the real Reminders and Microsoft To Do providers are implemented. It is not yet packaged as a released, signed macOS app (and the Microsoft side needs your own account connection). Source lives in a private GitHub repository.