Whitespace.
See who already built your idea — and the space they left open.

CLUSTER CALENDAR-CALENDARS-DEVICE · 12 ENTRIES · EARLIEST ENTRY 2026-01-16

Unified multi-calendar sync apps

This cluster consists of calendar apps that unify or sync multiple calendar sources—iCloud, CalDAV, ICS, Google, and Outlook—into one view, with variations around self-hosting, sharing, widgets, and write controls. The dated history before the index start is sparse: isolated single entries appear from April 2012 through November 2018, followed by a long gap and then a small recent cluster in late 2025 and mid-2026. Traction is led by Glimpse with 2 stars, while the other two named members, Google Calendar: Get Organized and KashCal, each have 0 stars.

Entry timeline

ENTRY TIMELINE

APR 2012: 1SEP 2015: 1MAY 2017: 1NOV 2018: 1NOV 2025: 1JAN 2026: 2JUN 2026: 1AUG 2026: 1OCT 2026: 3
APR 2012OCT 2026

Each bar is the month a member carries, which is a creation date where the source published one and a crawl date otherwise. Nothing in the index was found before 11 August 2026, and coverage broadened sharply on 14–15 August, so a bar from then on reports how much we found that month, not how much was built; an earlier bar reports how far back a member's own source dated it — not how long we have been watching.

Members by activity

Activity signals, not revenue.

Build origin · 1 ai-built · 1 hand-coded · 10 unlabelled

Operator · 3 hobby · 1 indie · 3 commercial · 2 open source · 3 unlabelled

Two labels per entry, never collapsed into one: how it was built, and who stands behind it. Counted over the 12 listed below. Unlabelled means nothing has decided yet — not that the answer is small.

  1. 01Glimpse2★2 days—hobbySelf-hosted calendar app that merges Google, Outlook, and iCloud calendars and shares filtered schedule views with different people.
  2. 02KashCal0★16 daysliveopen sourceCalendar app that unifies iCloud, CalDAV, device, and ICS calendars into one view with scheduling, widgets, and on-device time insights.
  3. 03outlook-google-calendar-bridge0★7 days—Self-hosted calendar sync app that aligns Outlook and Google calendars, offering previews, bounded writes,and private event defaults.
  4. 04icsms3★1 mo—hand-codedSelf-hosted calendar app that manages iCalendar subscription feeds from multiple sources and organizes their events for users.
  5. 05kalendra-ai0★9 days—hobbyCross-platform calendar assistant that unifies Google and Outlook calendars and proposes scheduling actions with user confirmation.
  6. 06SimpleCal: Simple Calendar0★18 dayslivecommercialCalendar app that syncs with iCloud or Google, displays weather widgets, reminders, and customizable color themes.
  7. 07scheduly2★3 moliveWeb app that converts academic schedule PDFs into digital ICS calendars for Google Calendar, Apple Calendar, and Outlook.
  8. 08Simple Calendar Daily Planner0★23 dayslivecommercialSimple Calendar is a minimalist calendar app that syncs with iCloud and Google Calendar, offers widgets, customization, and sharing features.
  9. 09smart-sync-google-calendars2★10 mostale—ai-builthobbyTool that synchronizes events from multiple Google Calendars into a single unified calendar view automatically.
  10. 10Calendar Import-Export0★2 yrabandonedliveopen sourceMobile app that imports, exports, and backs up calendar data as ICS files without relying on cloud synchronization services.
  11. 11comingup-today0★8 mostaleliveindieScheduling app that aggregates multiple calendars into one shared read-only view for families and small teams coordinating schedules.
  12. 12Tiny Calendar: Planner & Tasks0★11 mostalelivecommercialCalendar app that syncs Google and other calendars, offering natural language input, multiple views, reminders, and offline editing for iPhone and iPad users.

Ranked by traction, highest first, and paged 20 at a time — this is a window on the cluster, never the whole of it. Ties are broken by a stable id so a product cannot appear on two pages or fall between them. Browse every cluster.