Microsoft Office 365 calendar -> Google calendar

Overview

One-way sync from a Microsoft Office 365 Outlook calendar to a Google calendar, handling new, updated, and deleted events.

The script connects to the Microsoft API using the O365 package and connects to the Google API using its Python client. Familiarize yourself with their documentation as you may need to enable APIs or create credentials per their instructions before you begin. See also the Google Calendar API reference.

Setup

• Create config.py (you can adapt config_sample.py) to hold your personal configuration details, include your Microsoft client_id and client_secret and your Google calendar ID.
  • Create a new Google calendar just for this application, or else your existing events will be deleted!
  • Create Google credentials for this application (see overview section above) and save as credentials/google_credentials.json.
  • Get the Microsoft client_id and client_secret by following the O365 instructions on how to authenticate on behalf of a user.
• Run uv sync to install the required Python dependencies into a virtual environment.
• In the credentials folder, run python quickstart.py to create a Google API access token.
• Microsoft API access token is created interactively via URL on first run, then permanently stored. It expires in 90 days if you don't run the script within that time.
• On your server, set up a cron job to run outlook_to_google.py (using run.sh) every 15 minutes (or however often you need).
• The script will check Microsoft for calendar events and compare them to the calendar events it saved (in events_ts.json) during the previous run. If they differ (in IDs or timestamps), it will delete all events on this Google calendar and then add all Microsoft calendar events to the Google calendar.