Sundy

Cross-platform calendar app with intelligent cross-calendar time management.

Why This Project?

I'm building Sundy because:

• I want to - it's a passion project that excites me
• I need specific features I've wanted for a while:
  • Seamless cross-calendar integration and management
  • ADHD-friendly features to help with time management
  • Smart features to prevent missing meetings
  • Reliable, configurable notifications
• Daily use - this solves real problems I face every day
• Speed matters - I want a fast, lightweight experience
• Privacy-first - my data stays mine, always

The Problem

Here's my reality:

• I have a Gmail calendar
• I have multiple Outlook calendars
• Some things sneak into my Apple Calendar
• My wife uses Reminders and the paper calendar on our wall

And here's what happens:

1. Calendar A gets blocked, but B and C don't know about it
2. Calendar B gets scheduled later and silently conflicts with A
3. Calendar C's notifications are muted, or I only see Calendar A because that's my work computer
4. Where do I put family events? Doctor appointments for me, my wife, the kids... all of them?
5. No easy way to navigate all of this—add ADHD and object permanence issues and... "Oops, sorry, can't make that meeting today"
6. "Hey, are you joining the meeting?" — "Oh crap! I didn't get that notification!"

Features

• Offline-first - works without an internet connection
• Fast & responsive - efficient rendering and sync
• Privacy-focused - your data stays yours
• Clean, minimal UX - no clutter, just what you need

Demo

Try the browser version: https://try.sundycal.com

Note:

• This is a very basic demo of the browser version, which is not as well tested as the desktop version
• The browser version may be slower and have a larger footprint than normal
• Data is stored in memory and will not be persisted

Getting Started

Prerequisites

• .NET 10.0 SDK or later

Running the Desktop App

1. Clone the repository:

   git clone https://github.com/codymullins/Sundy.git
   cd Sundy

2. Restore dependencies:

   dotnet restore

3. Run the desktop application:

   dotnet run --project src/Avalonia/Sundy.Desktop/Sundy.Desktop.csproj

Alternatively, you can navigate to the desktop project directory and run directly:

cd src/Avalonia/Sundy.Desktop
dotnet run

sundy.mp4

License

Sundy Calendar is licensed under the O'Saasy License — a source-available license that grants broad permissions while protecting against competing commercial offerings. See osaasy.dev for the full license text.

What you can do

• Use Sundy Cal on your own devices for personal or work purposes
• Deploy it across your organization for internal use (any company size)
• Fork, modify, and redistribute Sundy Cal for free
• Build and share free tools or integrations that use Sundy Cal
• Offer consulting, setup, or customization services to clients
• Integrate Sundy Cal into a free, non-commercial product or service

What requires a commercial license

• Offering a hosted or SaaS product where calendar functionality is a core feature
• Integrating Sundy Cal into any product or service that generates revenue (sales, subscriptions, ads, donations, sponsorships, etc.)
• Reselling, white-labeling, or rebranding Sundy Cal
• Building a sync, backup, or notification backend that competes with Sundy Server

The short version

If you're not making money from it and not competing with Sundy's offerings, you're good. If money is involved or you're building something that replaces what we sell, let's talk.

Questions?

If you're unsure whether your use case requires a commercial license, reach out at licensing@voltern.net.