Gradescope to Cal

A privacy-first browser extension that automatically syncs Gradescope assignments to Google Calendar.

Current Version: v1.9.1 — Available on Chrome Web Store & Firefox Add-ons

Features

Core Functionality

• Automatic dashboard discovery: Extracts all assignments from all enrolled courses
• Four intelligent sync mechanisms:
  • First-time sync: Immediate sync when you first connect your calendar
  • Manual sync: User-triggered sync on-demand
  • 24-hour auto-sync: Scheduled background updates (configurable)
  • Smart sync on extraction: Instant sync when new assignments detected (60-min cooldown)
• Smart deduplication: Prevents duplicate events for the same assignments
• Upcoming assignments only: Automatically filters out past assignments to keep your calendar clean

Calendar Integration

• Google Calendar sync: Creates rich calendar events with assignment details and direct Gradescope links
• iCal export: One-time export for Outlook, Apple Calendar, and other calendar apps
  • RFC 5545 compliant .ics files
  • Enhanced Outlook compatibility with clickable links
  • Respects all your customization preferences

Event Customization

• Event colors: Choose from 11 Google Calendar colors to match your style
• Flexible reminders:
  • None, single (1 day), double (1 day + 1 hour), or custom (up to 3 reminders)
  • Customizable reminder timing to fit your workflow
• Display timing:
  • Deadline time (default): Shows event at actual due time (e.g., 11:59 PM)
  • All-day event: Shows at top of calendar for maximum visibility

User Experience

• Dark mode support: Toggle between light and dark themes for comfortable viewing
• Interactive onboarding: First-time user tutorial to get you started quickly
• Context-aware UI: Smart interface that adapts to your current Gradescope page

Privacy & Architecture

• Zero-server architecture: All processing happens locally in your browser
• Cross-browser support: Chrome/Chromium (Manifest v3) and Firefox compatible

Privacy First

• No external servers: All data processing occurs locally in your browser
• No data collection: We never see your assignments, grades, or personal information
• Direct API integration: Your data goes directly from your browser to Google Calendar
• Minimal permissions: Only accesses Gradescope and Google Calendar APIs
• Open source: Full transparency, you can inspect the code yourself

Installation

Chrome/Chromium Browsers

Install from Chrome Web Store

Firefox

Install from Firefox Add-ons

How It Works

1. One-time setup: Install the extension and connect your Google Calendar via secure OAuth authentication
2. Automatic extraction: Visit any Gradescope page - assignments are automatically discovered and extracted
3. Instant first sync: On first authentication, all extracted assignments immediately sync to your calendar
4. Stay updated automatically: Four sync mechanisms keep your calendar current:
   • First-time sync: Immediate sync when you connect your calendar
   • Manual sync: Click "Sync to Calendar" button anytime
   • 24-hour auto-sync: Daily background updates (can be disabled in settings)
   • Smart sync: Instant sync when new assignments are detected (60-min cooldown)
5. Customize your events: Set colors, reminders, and display timing in the options page
6. Export if needed: Generate iCal files for Outlook, Apple Calendar, or other calendar apps
7. Cross-device access: Calendar events sync to all your devices via Google Calendar

Version History

v1.9.2 (Current) - Bug Fixes

• Fixed visual bug with extracted assignment count and fixed first stage of redundant deduplication logic

v1.9.1 - Firefox Compatibility

• Fixed Firefox compatibility for iCal export (message passing bug fix)

v1.9.0 - iCal Export

• iCal export feature for Outlook, Apple Calendar, and other calendar apps
• RFC 5545 compliant .ics file generation with UTC format
• Enhanced Outlook link accessibility (URL in LOCATION field)
• Title format consistency with Google Calendar API events
• Proper description newline formatting

v1.8.0 - Smart Sync & Architecture

• Modular architecture refactor for improved maintainability
• Improved pin detection for browser toolbar
• Smart sync on extraction (instant sync for new assignments)

v1.7.0 - Dark Mode

• Added dark mode support with theme toggle
• CSS variable-based theming system
• Consistent dark mode across popup and options pages

v1.6.0 - Enhanced Auto-Sync

• 24-hour auto-sync intervals with configurable settings
• Auto-sync toggle in options page

v1.5.1 - Initial Public Release

• Chrome Web Store publication
• Core calendar sync functionality
• OAuth authentication and token management

Development Status

• Competitive analysis and architecture planning
• Gradescope assignment data extraction (dashboard + individual courses)
• Google Calendar API integration with OAuth 2.0
• Background sync automation (daily intervals + smart detection)
• Rich calendar event creation with assignment metadata
• Smart deduplication and error handling
• Event customization (colors, reminders, display timing)
• Dark mode support with theme system
• iCal export for non-Google calendar apps
• Cross-browser compatibility (Chrome/Chromium + Firefox)
• Privacy policy and web store preparation
• Chrome Web Store & Firefox Add-ons publication

Technical Architecture

• Content Scripts: Extract assignment data from Gradescope pages with intelligent parsing
• Background Service Worker: Handles OAuth authentication, calendar sync, and auto-sync scheduling
• Event Cache: Performance layer with 10-minute refresh cycle, handles up to 1000 events
• Dual Authentication Strategy:
  • Chrome/Chromium: Native chrome.identity.getAuthToken() for fast authentication
  • Firefox: PKCE OAuth flow with refresh tokens
• Local Storage: Stores assignment data and user preferences in browser
• Google Calendar API v3: Creates and manages calendar events with extended properties for deduplication
• iCal Generator: RFC 5545 compliant .ics file generation for universal calendar compatibility
• Zero external dependencies: No servers, databases, or third-party services

Current Limitations

• Assignment discovery: Requires visiting Gradescope pages to detect new assignments (auto-extracts on page load)
• Course coverage: Works with standard Gradescope course layouts
• Google Calendar sync: Requires Google account with Calendar access
• iCal export: One-time export without deduplication tracking (re-importing the same .ics file will create duplicates)

Privacy Policy

Full privacy policy available at: Privacy Policy

Support

• Issues: Report bugs via GitHub Issues
• Email: [email protected]
• Primary audience: Gradescope users worldwide

Development

Prerequisites

• Chrome/Chromium or Firefox browser
• Google Cloud Console project with Calendar API enabled
• Basic understanding of browser extension development (Manifest v3)

Setup

1. Clone this repository
2. Update CLIENT_ID in background.js with your Google OAuth client ID
3. Load extension in developer mode:
   • Chrome: Extensions → Developer Mode → "Load unpacked" → select src/ folder
   • Firefox: about:debugging → "This Firefox" → "Load Temporary Add-on" → select manifest.json
4. Test with your actual Gradescope courses

Testing

When making changes, test:

• Dashboard extraction (multiple courses)
• Individual course page extraction
• Calendar event creation with custom colors/reminders
• All four sync mechanisms (first-time, manual, 24-hour, smart sync)
• iCal export functionality
• Dark mode toggle
• Cross-browser compatibility (Chrome + Firefox)

Contributing

Contributions welcome! Please read the code to understand the privacy-first architecture before making changes.

License

MIT License - feel free to fork and improve!

Acknowledgments

Built for UC Berkeley students. Usable by all Gradescope users. Inspired by the need for better assignment tracking without compromising privacy.