Integrating Exchange Calendars with Home Assistant

General
1

Hey everyone! I’m really excited to share something I’ve been working on for a while now. I’ve just released an integration for Home Assistant that connects directly to Microsoft Exchange calendars, both on-premise and Office 365. This has been a project close to my heart, and I can’t wait to hear what you all think!

What It Does

If you’re using Microsoft Exchange at work, you’ve probably noticed there’s no easy way to bring your corporate calendar into Home Assistant. This integration fills that gap by connecting directly via EWS (Exchange Web Services). Here are some of the key features:

  • Full CRUD support: Read, create, update, and delete calendar events directly from HA
  • On-premise Exchange with NTLM authentication
  • Office 365 / Microsoft 365 with OAuth2 (Azure AD app registration)
  • Automatic recurring event expansion
  • Voice assistant compatible – works with HA Assist / Voice PE
  • Self-signed SSL certificate support
  • Configurable polling interval, date range, and event limits
  • English and Hungarian UI translations

Why I Built It

I originally created MMM-Exchange for MagicMirror² to display my corporate Exchange calendar on a smart mirror. People kept asking for a Home Assistant version, so I ported it to Python and built a proper HA integration with full config flow and service support. The real power comes from automations – for example, I get a notification 15 minutes before every meeting, and my office lights change color when I’m in a meeting so my family knows not to disturb me.

Example Automation

Here’s a quick example of how you can set it up:
yaml
automation:

  • alias: “Meeting reminder”
    trigger:
    • platform: calendar
      event: start
      entity_id: calendar.exchange_your_email
      offset: “-00:15:00”
      action:
    • service: notify.mobile_app
      data:
      message: “Meeting starts in 15 minutes!”

Installation

  1. Add it via HACS → Custom repositories
  2. Repository URL: https://github.com/bohemtucsok/homeassistant-exchange-calendar
  3. Category: Integration
  4. Install, restart, and configure via the UI

What’s Next

I’m actively developing this integration and would love your feedback! If you have feature requests or run into issues, please open a GitHub issue. Star the repo if you find it useful – it helps with visibility!

I hope this integration can help you bring your corporate calendar into Home Assistant as seamlessly as it has for me. Let me know what you think!