One Calendar#

A privacy-first, weekly-focused open-source calendar built for clarity and control.

Vision#

Most modern calendar tools are overloaded with automation, notifications, and analytics.
One Calendar takes a different approach:

Respect user privacy.
Provide a smooth, local-first planning experience.
Keep the system understandable.

This project is built for individuals and small teams who value clarity over complexity.

Features#

Weekly planning#

Drag & drop scheduling – move and resize events directly on the calendar
Inline editing – create and update events without modal overload
Right-click actions – fast contextual controls for power users
Keyboard-friendly interactions – efficient navigation and editing workflows

Event management#

Rich event metadata – title, description, time range, and structured fields
Precise time control – flexible duration handling and adjustments
Instant updates – optimistic UI for a responsive experience
Event persistence – reliable storage with Drizzle
Soft state handling – controlled updates to avoid accidental data loss

Privacy & security#

No AI tracking – no behavioral profiling or data mining
No analytics by default – zero third-party tracking scripts
User-controlled exports – backup and portability without lock-in
Secure authentication – hardened session management via Better Auth

Sync & collaboration#

Cloud sync (optional) – multi-device synchronization using Drizzle
Account-based access – sign in with third-party providers
Share-ready architecture – designed for future team and shared calendar support

Customization & UX#

Theme configuration – adaptable visual styling
Default view control – choose how your calendar opens
Locale-aware formatting – proper date and time formatting per region
Internationalization (i18n) – language support built-in
Composable UI system – built with reusable components (shadcn/ui + Tailwind)

Comparison with other calendar tools#

Feature	One Calendar	Google Calendar	Apple Calendar	Outlook Calendar	Proton Calendar
Event creation & editing	✅	✅	✅	✅	✅
Drag & drop scheduling	✅	✅	✅	✅	✅
All-day events	✅	✅	✅	✅	✅
Event reminders & notifications	✅	✅	✅	✅	✅
Time zone support	✅	✅	✅	✅	✅
Calendar sharing	✅	✅	✅	✅	✅
Multiple calendar views (day/week/month)	✅	✅	✅	✅	✅
Keyboard shortcuts	✅	✅	⚠️	✅	✅
Search events	✅	✅	✅	✅	✅
Quick add / natural input	✅	✅	⚠️	✅	⚠️
Cloud sync	✅	✅	✅	✅	✅
Web application	✅	✅	⚠️	✅	✅
Privacy-first architecture	✅	❌	⚠️	❌	✅
No analytics / tracking by default	✅	❌	⚠️	❌	✅
Open-source	✅	❌	❌	❌	⚠️
Self-hostable	✅	❌	❌	❌	❌
Data export	✅	✅	✅	✅	✅
ICS import / export	✅	✅	✅	✅	✅

⚠️ = limited or partial support

Getting Started#

Prerequisites#

Required Versions:

NodeJS (v20 or higher)
pnpm

Quick Start#

# Clone the repo
git clone https://github.com/EvanTechDev/One-Calendar.git
cd One-Calendar

# Install dependencies
pnpm install

# Start the app
pnpm dev

Then visit http://localhost:3000

Environment Variables#

Copy .env.example to .env and fill in.

Key variables:

# Core
NEXT_PUBLIC_BASE_URL=http://localhost:3000
SALT=Backup-Salt

# Auth
BETTER_AUTH_SECRET=secret
BETTER_AUTH_URL=http://localhost:3000

# Optional
POSTGRES_URL=postgres://postgres:postgres@localhost:5432/onecalendar
BETTER_AUTH_API_KEY=your-api-key
NEXT_PUBLIC_TURNSTILE_SITE_KEY=site-key
TURNSTILE_SECRET_KEY=secret-key

Database Configuration#

This project uses Drizzle ORM.

After configuring POSTGRES_URL, run:

# Push schema to database
pnpm dlx drizzle-kit push

Production Recommendation#

For production deployments, use migrations:

# Generate migrations
pnpm dlx drizzle-kit generate

# Apply migrations
pnpm dlx drizzle-kit migrate

Tech Stack#

Stack

Contributing#

Contributions are welcome! Feel free to explore the project and submit improvements.

Please refer to CONTRIBUTING.md for setup instructions and contribution guidelines.

License#

Made with ❤️

Published under MIT License.

This project is supported by Cloudflare Project Alexandria.

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