Encrypted operational data
OAuth tokens and event cache data are encrypted at rest. The service also keeps sync state and event mappings needed to reconcile updates and deletes.
Trust-first calendar sync.
Calendar permissions are sensitive. Calendar Syncer is designed around one-way sync, narrow defaults, encrypted operational data, and visible disconnect controls.
How the design protects your calendars
Mapped shadow events
Event mappings connect an Outlook source event to its Google shadow event so cancellations and deletes can be applied correctly.
Webhook and billing state
Webhook and subscription state, billing and subscription state, and operational sync logs support recovery, access gates, debugging, and abuse prevention without claiming that no event data is stored.
What the product expects to store
The service stores operational calendar data because continuous sync requires state. These are the public disclosures baked into the product direction:
- Encrypted OAuth tokens
- Encrypted event cache
- Sync state and event mappings
- Webhook and subscription state
- Billing and subscription state
- Operational sync logs
Calendar Syncer is operated by Philip Reichen Software, a Swiss sole proprietorship (Einzelunternehmen) at Hohlstrasse 206, 8004 Zurich, Switzerland. Not VAT registered; Swiss VAT/MWST is not charged while the business is not registered for VAT.
Security questions
What access does the app request on my Microsoft account?
Read-oriented calendar access: enough to read events and receive change notifications. The app never creates, edits, or deletes anything in your Outlook calendar — one-way sync means the Microsoft side is a source, not a destination.
What access does the app request on my Google account?
By default, the narrow app-created-calendar scope: the app can create and manage its own calendar and the events in it, but cannot touch your other Google calendars. The optional advanced flow adds scopes to list your calendars and write to one you own, only if you choose it.
Is my calendar data encrypted?
Yes. OAuth tokens and cached event data are encrypted at rest, alongside the sync state and event mappings needed to apply updates and deletes correctly. Operational logs are kept minimally, with a launch target of up to 30 days.
How do I revoke access?
Two independent ways: disconnect from the app's Settings (which stops sync immediately and lets you delete stored sync data), or revoke the app in your Microsoft account (account.live.com/consent/Manage or myapps.microsoft.com) and Google account (myaccount.google.com/connections) — provider-side revocation takes effect as the app's short-lived tokens expire.
Do I need my IT department's approval to connect a work account?
It depends on your organization's app-consent policy. Access is requested through Microsoft's standard OAuth consent flow — visible and auditable to IT — and many tenants allow users to consent to low-privilege, read-oriented apps themselves. If your tenant requires admin consent, Microsoft's flow routes the request to your admin automatically.
How do I report a security issue?
Email philthebrogrammer@gmail.com. The site also publishes contact details in the standard /.well-known/security.txt location (RFC 9116) so researchers can find the disclosure channel automatically.