In Active Development

One calendar to
rule them all

Cross-platform calendar with intelligent cross-calendar time management. Built for people juggling Gmail, Outlook, Apple Calendar, and life.

Demo runs in-browser • Data is not persisted

Sound familiar?

You've got a Gmail calendar. Multiple Outlook calendars. Things sneaking into Apple Calendar. Your spouse uses Reminders and a paper calendar on the wall.

Calendar A gets blocked, but B and C don't know about it. Calendar B gets scheduled later and silently conflicts. You miss the notification because you're on the wrong computer.

"Hey, are you joining the meeting?"

"Oh crap—I didn't get that notification!"

See it in action

A quick look at Sundy syncing with Outlook calendar.

Built different

Cross-Calendar Sync

See all your calendars in one place. Block time across providers automatically so double-booking becomes impossible.

Offline-First

Works without internet. Fast, responsive, and always available when you need it.

ADHD-Friendly

Smart features to help with time blindness and object permanence. Reliable notifications you can actually configure.

Privacy-First

Your data stays yours. No tracking, no selling your schedule to advertisers.

Free to use, pay for convenience

Sundy is free and always will be. Optional paid features handle the hosting so you don't have to.

Free

Sundy Core

  • Full desktop, mobile, and browser app
  • Local calendar synchronization
  • Bring your own notifications
  • All core features, no limits
Paid

Sundy Cloud

  • Hosted synchronization across devices
  • Cloud backups
  • Text message notifications
  • Email notifications

$50/year

Open Source

Built with .NET and Avalonia. Runs on Windows, macOS, Linux, iOS, and in the browser. Android coming later.

codymullins/Sundy
Star on GitHub

Want to follow along?

Sundy is a passion project in active development. Star the repo to get notified of releases, or try the demo to see where it's headed.