CalSync 📅

A lightweight, stateless Google Apps Script that automatically mirrors your personal calendar events as private holds on your work calendar.

Protect your time without leaking personal details or dealing with messy third-party calendar sync tools.

Features

• Privacy First: Creates opaque [DNS] External Appointment holds on your work calendar. By default, these are set to private so colleagues only see that you are busy (configurable).
• Smart Work Hours: Automatically clamps personal events to fit within your designated work hours (e.g., 9 AM to 5 PM).
• Weekend & OOO Detection: Ignores events on weekends and events that are fully covered by an existing "Out of Office" block on your work calendar.
• Duration Limits: Automatically ignores all-day events or events that span longer than a configurable threshold (defaults to 8 hours).
• Stateless & Resilient: Uses a rolling 28-day window and private extended properties. It cleans up orphaned holds naturally, ignores infinite recurrences, and safely supports multiple people using CalSync on shared events.

Prerequisites

1. A Google Work account (where the script will run).
2. One or more Personal Google accounts.
3. Your Personal calendar(s) must be shared with your Work account with "Make changes to events" or "See all event details" permissions. (Note: Sharing as "See only free/busy" will not work).

Installation

1. Share your Personal Calendar:

   • Go to Google Calendar on your personal account.
   • Go to Settings > Settings for my calendars > [Your Calendar].
   • Scroll to "Share with specific people or groups", add your work email, and grant permission to "Make changes to events" (or at least "See all event details").

2. Create the Script:

   • Log into your work account and go to script.google.com.
   • Click New Project.
   • Delete any placeholder code and paste the contents of Code.js from this repository.

3. Configure:

   • At the top of the script, update the CONFIG object.
   • Replace 'your.personal@email.com' with your actual personal calendar email address(es).
   • Adjust workStartHour, workEndHour, maxHoldHours, and holdVisibility if necessary.

4. Enable Calendar API:

   • On the left sidebar of the Apps Script editor, click on Services (the + icon).
   • Scroll down, select Google Calendar API, and click Add.

5. Run the Setup:

   • In the toolbar at the top of the editor, select the install function from the dropdown menu.
   • Click Run.
   • Google will prompt you to review permissions. Click Review Permissions, choose your work account, click Advanced, and then click Go to [Project Name] (unsafe). Click Allow.

That's it! CalSync will now run automatically in the background every 5 minutes.

Uninstalling

If you ever want to stop syncing and remove the generated holds from your work calendar:

1. Open your Apps Script project.
2. Select the uninstall function from the top toolbar dropdown.
3. Click Run. This will delete the 5-minute trigger and sweep your work calendar to remove any active holds it created.