BusySync

Google Apps Script that syncs your personal and work Google Calendars — keeping your personal events private from work while mirroring work events back to you.

The Problem

You have two Google accounts (personal + work). You need:

• Colleagues to see you as busy when you have personal events
• To see your work events from your personal devices
• No personal event details visible to your work account

Google has no built-in way to do this.

How It Works

Two one-way syncs running every 5 minutes:

1. Busy Sync (Personal → Work)

Queries your personal calendar's free/busy times via the FreeBusy API and creates [Busy] blocks on your work primary calendar. Colleagues see you as unavailable. No event titles, descriptions, or attendees are exposed — just time ranges.

2. Mirror Sync (Work → Personal)

Copies your work events to a secondary "Work Mirror" calendar using Events.import() (no attendee notifications). Subscribe to this from your personal account instead of your primary work calendar. The busy blocks from sync #1 are excluded, so you don't see doubled events.

Mirror events are prefixed with [brackets] so you can tell them apart from real events at a glance.

Privacy

• Work sees: Generic [Busy] blocks with no details (marked as private + opaque)
• Personal sees: Work event titles, times, locations, and attendee names (as plain text in the description — no email addresses in the attendees field)
• Colleagues see: Nothing different — the busy blocks just look like you blocked time
• No emails are sent to anyone — Events.import() never triggers notifications

Setup

1. Share your personal calendar with your work email as "See only free/busy (hide details)" (from your personal account)

2. Create an Apps Script project at script.google.com from your work account. Paste sync.gs.

3. Set PERSONAL_CALENDAR_ID to your personal Gmail address.

4. Create a "Work Mirror" calendar on your work account: Google Calendar → + next to "Other calendars" → Create new calendar → name it exactly Work Mirror.

5. Enable the Google Calendar API advanced service: Editor sidebar → Services (+) → Google Calendar API → Add.

6. Set the manifest: In the Apps Script editor, go to Project Settings → check "Show appsscript.json in editor" → replace contents with appsscript.json from this repo.

7. Run initialSetup. Authorize when prompted.

8. Share "Work Mirror" with your personal email: Google Calendar → Settings → Work Mirror → Share with specific people → your personal email → "See all event details".

9. Subscribe to the Work Mirror calendar from your personal account.

10. Unsubscribe your personal account from your primary work calendar.

Teardown

Run teardown() in the Apps Script editor. It removes all synced events from both calendars and deletes the trigger. The Work Mirror calendar itself is left intact (you created it manually).

Required Scopes

Scope	Why
calendar.events	Create/delete busy blocks and mirror events
calendar.freebusy	Query personal calendar availability
calendar.readonly	Look up the mirror calendar by name
script.scriptapp	Create/manage the 5-minute trigger
script.send_mail	Email you if the sync fails
userinfo.email	Get your email for failure notifications

Notes

• All-day personal events only sync if explicitly set to "Busy" (Google defaults them to "Free")
• The FreeBusy API merges adjacent busy periods — two back-to-back personal events become one [Busy] block
• Conference/Meet links are included in mirror events so you can join directly
• Uses LockService to prevent concurrent sync runs from colliding
• Only mirrors default, fromGmail, and focusTime event types