A decentralized calendar application built on the Nostr protocol. NostrCal enables users to create, discover, and manage calendar events in a censorship-resistant, peer-to-peer environment using NIP-52 calendar events.
- 📅 Calendar Events: Create and manage date-based (NIP-52 kind 31922) and time-based (NIP-52 kind 31923) calendar events
- 🔍 Event Discovery: Browse and search public calendar events with advanced filtering (by time, location, tags)
- 📱 RSVP Support: Respond to calendar events with NIP-52 kind 31925 RSVPs
- 🔐 Nostr Authentication: Secure login using Amber signer (NIP-55) for Android
- ⚡ Real-time Updates: Live event streaming from Nostr relays with local-first architecture
- 🎨 Material 3 Design: Modern, accessible interface with light/dark theme support
- 📄 Pagination: Efficient event loading with exponential pagination (100→200→400→800→1600)
- 🏷️ Rich Event Details: Support for titles, descriptions, locations, images, participants, hashtags, and references
- 📊 Custom Availability: Extended NIP-52 implementation with calendar availability templates and privacy-preserving busy blocks
NostrCal implements and extends the NIP-52 specification:
- NIP-52 Core: Date-based events (31922), time-based events (31923), calendars (31924), RSVPs (31925)
- NIP-52 Extensions: Calendar availability (31926) and availability blocks (31927) for booking systems
- NIP-55: Android signer integration with Amber
- NIP-44: Encryption support for private events
Built with the Purplestack development framework, featuring:
- Flutter: Cross-platform mobile development
- Riverpod: Reactive state management
- Purplebase: Local-first Nostr SDK with SQLite storage
- Material 3: Modern design system
- Table Calendar: Interactive calendar widget
- Android device (arm64-v8a architecture)
- Amber Signer installed for Nostr authentication
Download the latest APK from the releases or build from source.
# Clone the repository
git clone <repository-url>
cd purplestack
# Install dependencies
fvm flutter pub get
# Build APK
fvm flutter build apk --target-platform android-arm64 --split-per-abiThis project uses the Purplestack development stack designed for AI agents to build Nostr-enabled Flutter applications.
For MacOS (may work with Homebrew on Linux) and just for guidance. View the respective projects' documentation for more.
# Install Android
brew install android-commandlinetools
# add to shell's rc file ANDROID_SDK_ROOT=/opt/homebrew/share/android-commandlinetools
# Install Java
brew install openjdk@17
# Install Dart
brew tap dart-lang/dart
brew install dart
dart --disable-analytics
dart pub global activate fvm
# Install Flutter
fvm releases
fvm install <version>
sdkmanager --install "platforms;android-35"
sdkmanager --install "build-tools;35.0.0"
sdkmanager --install emulator platform-tools tools
sdkmanager --licenses
sdkmanager --install "system-images;android-30;google_apis;arm64-v8a"
avdmanager create avd --name "pixel_8" --package "system-images;android-35;google_apis;arm64-v8a" --abi "arm64-v8a" --device "pixel_8"MIT