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Cesium Events Privacy Policy

Last updated · 2026-05-10 · v2.1

Cesium Events is a native macOS app. Its job is to read your calendar events and show you a full-screen reminder when one is about to start. To do that, it asks for read-only access to whichever calendars you connect (Apple Calendar, Google Calendar, Microsoft 365 / Outlook, or any combination) and nothing more. This document explains exactly what data the app reads, where that data lives, which network hosts the app talks to, and what the app deliberately does not do.

v1 of Cesium Events read only from Apple Calendar and made no network calls. v2 added direct integrations with Google Calendar and Microsoft 365 / Outlook, which require talking to Google and Microsoft over the internet. The "Network connections" section below lists every host the app contacts and why.

What Cesium Events reads

Per event

  • Title (event subject / summary)
  • Start and end time, including time zone for Outlook events
  • Location, when present
  • Description / body, used to detect meeting URLs (Zoom, Teams, Meet, Webex, etc.) so a "Join" button can appear on the notification card. From Google, the full description is fetched; from Outlook, only the first ~255 characters (Microsoft Graph's bodyPreview field) are requested. Apple Calendar event notes are read locally via EventKit when present.
  • Calendar name and color, so events can be visually attributed to the calendar they came from
  • Status (e.g., cancelled), all-day flag, and any embedded conference / online-meeting URL

Per connected account

  • Email address (from Google's userinfo endpoint or Microsoft Graph's /me)
  • Display name
  • Profile picture URL, when Google provides one. The URL string is stored so it can be shown in the Settings UI; the image itself is not downloaded or cached by Cesium Events
  • List of calendars available on that account (calendar IDs, names, and colors), so you can choose which ones notify you

What Cesium Events stores on your Mac

Apple Calendar events: in memory only

Apple Calendar events are read locally through macOS's EventKit framework. Nothing is sent over the network and nothing is written to disk. Cesium Events holds events in memory while running and refreshes them when macOS notifies it of changes.

Google & Outlook events: in memory only

Events fetched from Google Calendar or Microsoft Graph are held in memory while the app is running and are not written to disk. Closing the app discards them; reopening re-fetches from the provider.

Calendar lists: cached on disk

To remember which calendars belong to which account when the app launches (and to keep working briefly during a network blip), the list of calendars for each Google or Outlook account is cached as JSON in ~/Library/Application Support/Cesium Events/ as google_cache_<accountID>.json or outlook_cache_<accountID>.json. These files contain calendar IDs, calendar names, and calendar colors. Nothing else. No event titles, times, attendees, or other event details are written to disk. The cache is overwritten on the next sync and deleted when the account is disconnected.

Account metadata: on disk

A single JSON file at ~/Library/Application Support/Cesium Events/accounts.json tracks the accounts you've connected. For each account it stores: a randomly generated account ID, the account's source type (Apple, Google, or Outlook), email address, display name, profile-picture URL string (Google only, never the image), creation timestamp, last-sync timestamp, current sync status, and which scopes were granted. The file is written with user-only file permissions (0o600) and is deleted entirely when you remove the account inside Cesium Events.

OAuth tokens: Keychain

For Google and Microsoft accounts, the OAuth access token, refresh token, and token expiry are stored in your Mac's Keychain with the strictest accessibility class: kSecAttrAccessibleWhenUnlockedThisDeviceOnly. They never leave your device, are excluded from iCloud Keychain sync and device-migration backups, and cannot be read while your Mac is locked.

Settings & app state: UserDefaults

Your preferences live in macOS UserDefaults (~/Library/Preferences/com.jucius.Cesium Events.plist): which calendars are enabled, notification lead time, the pulsating-background toggle, the launch-at-login choice, onboarding completion flag, plus the trial start date and purchase status. None of this leaves your Mac.

Network connections

Cesium Events talks to exactly these hosts, and only these hosts. There is no Jucius Labs server, no analytics endpoint, no crash-reporting service, no telemetry collector. Every network call below is initiated as a direct consequence of an action you took inside the app (connecting an account, syncing your selected calendars, purchasing the app).

Google Calendar (when you connect a Google account)

  • accounts.google.com: OAuth authorization page (opens in your browser via Apple's ASWebAuthenticationSession)
  • oauth2.googleapis.com: token exchange, refresh, and revocation
  • www.googleapis.com: userinfo (email, display name, profile picture URL) and the Google Calendar API v3 endpoints used to fetch your calendar list and your events

Microsoft 365 / Outlook (when you connect a Microsoft account)

  • login.microsoftonline.com: OAuth authorization, token exchange, refresh, and sign-out
  • graph.microsoft.com: Microsoft Graph endpoints used to fetch your profile (display name, email), your calendar list, and your events

Apple App Store (purchases & trial)

Cesium Events uses Apple's StoreKit 2 framework for the 7-day free trial and the one-time in-app purchase. Apple's standard App Store servers handle product metadata, payment, and entitlement verification. No purchase data passes through any Jucius Labs system.

Apple Calendar

None. Events are read locally via EventKit. No network is involved.

Third-party calendar integrations

Google Calendar

Cesium Events requests one OAuth scope: https://www.googleapis.com/auth/calendar.readonly. This scope grants read-only access to your calendars and events. Even if Cesium Events wanted to write or delete an event, the scope wouldn't allow it. The OAuth flow uses PKCE (Proof Key for Code Exchange) and runs in your browser via macOS's ASWebAuthenticationSession; Cesium Events never sees your Google password.

You can revoke Cesium Events' access at any time, either by removing the account inside Cesium Events (Settings → Accounts → Disconnect, which also deletes the local tokens and cache), or by visiting myaccount.google.com/permissions and removing Cesium Events from the list.

Microsoft 365 / Outlook

Cesium Events requests three OAuth scopes from the Microsoft identity platform: Calendars.Read (read-only access to your calendars and events), offline_access (so the app can refresh tokens without forcing you to re-sign-in), and User.Read (so the app can read your display name and email). The flow uses PKCE and runs in your browser; Cesium Events never sees your Microsoft password. Calendar events are fetched via Microsoft Graph (graph.microsoft.com).

Revoke access through Settings → Accounts → Disconnect inside the app, or at myaccount.microsoft.com under "Apps and services that can access your data."

Data sharing and disclosure

Cesium Events does not share, sell, rent, transfer, or disclose your Google user data, your Microsoft 365 / Outlook user data, or your Apple Calendar data to any third party. Calendar information returned by your connected accounts stays on your Mac and is used only for the user-facing features of Cesium Events: showing your upcoming events in the menu bar dropdown and triggering full-screen notifications when an event is about to start.

Specifically, with respect to data read from Google, Microsoft, or Apple Calendar, Cesium Events does not:

  • Send your calendar events, calendar lists, account profile data, or OAuth tokens to any Jucius Labs server (there is no Jucius Labs server, and the app contacts no Jucius Labs domain)
  • Share, sell, rent, or otherwise transfer your data to advertisers, data brokers, analytics vendors, marketing partners, or any other third party
  • Use your Google, Microsoft, or Apple Calendar data to train, develop, evaluate, or improve any generalized or personalized machine-learning model, including large language models
  • Allow any human (including Jucius Labs employees, contractors, or service providers) to read your calendar data, except where you have explicitly shared it with us for a support request, the access is required for security purposes, or the access is required to comply with applicable law
  • Embed your data into any third-party SDK, library, or external service inside the app (Cesium Events has zero non-Apple runtime dependencies and zero analytics, telemetry, advertising, or crash-reporting integrations)

The only network parties that ever receive any data related to your connected accounts are the providers themselves (Google, Microsoft, and Apple's StoreKit servers for purchase verification). Those connections happen directly from your Mac to the provider over HTTPS, and only as needed to fetch the calendar information you have authorized or to verify a Mac App Store purchase. The exhaustive list of hosts Cesium Events contacts is in the "Network connections" section above.

Google API Services User Data Policy & Limited Use

Cesium Events' use and transfer to any other app of information received from Google APIs adheres to the Google API Services User Data Policy, including the Limited Use requirements. In particular:

  • We only use Google user data to provide or improve the user-facing features of Cesium Events that are prominently described in the app's interface (the menu-bar agenda and the full-screen pre-meeting notification)
  • We do not transfer Google user data to third parties, except as necessary to provide or improve those user-facing features, to comply with applicable law, or as part of a merger, acquisition, or sale of assets with notice to users (none of these transfers occur today, since Cesium Events has no backend and bundles no third-party SDKs)
  • We do not use Google user data for serving advertisements, including retargeted, personalized, or interest-based advertising
  • We do not allow humans to read Google user data, unless we have your affirmative agreement for specific messages, it is necessary for security purposes (such as investigating abuse), to comply with applicable law, or the data has been aggregated and anonymized for internal operations

What Cesium Events does not do

  • Share, sell, rent, transfer, or disclose your calendar data, account information, or OAuth tokens to any third party
  • Operate any Jucius Labs server that your data flows through (there is none)
  • Run analytics, telemetry, usage tracking, or crash reporting of any kind
  • Bundle any third-party SDK, analytics library, ad library, or external dependency (zero non-Apple dependencies)
  • Use cookies, device identifiers, advertising IDs, or any persistent tracker
  • Write to your calendars (read-only by OAuth scope on Google and Microsoft; the app simply does not call any write API on Apple Calendar)
  • Read events from calendars you haven't enabled in Settings → Calendars
  • Download or cache your profile picture from Google or Microsoft (only the URL string is stored)
  • Persist event details (title, time, location, description, attendees) to disk
  • Phone home for software updates (updates ship through the Mac App Store)

Permissions

Apple Calendar: Full Calendar Access

Apple's API does not offer a read-only calendar permission, so the macOS prompt asks for Full Calendar Access. Cesium Events only ever reads. You can revoke at any time in System Settings → Privacy & Security → Calendars, though doing so will hide all Apple Calendar events from Cesium Events.

Google & Microsoft: Read-only OAuth

The scopes requested are read-only by design (described above). No microphone, camera, location, contacts, photos, or filesystem access is ever requested.

Internet connection

Apple Calendar works fully offline. Google and Outlook accounts sync over the internet (every five minutes by default; configurable per account between 1 and 120 minutes). Without a connection, Cesium Events continues to display the most recently fetched events from those providers and notifies you of them; their list of calendars is restored from the on-disk cache described above.

Logging

Cesium Events writes diagnostic logs through Apple's unified logging system (os.Logger). Sensitive content (OAuth tokens, full API response bodies) is annotated as private so it is masked when logs are exported, and OAuth tokens are never logged in plain text. The app does not bundle any third-party logging or crash-reporting service. macOS retains its own unified log; you can view, export, or clear it via Console.app.

Data security

OAuth tokens are stored in macOS Keychain with device-only, while-unlocked accessibility. Network calls to Google and Microsoft happen exclusively over HTTPS (TLS). PKCE guards the OAuth flow; the OAuth state parameter is verified to defend against CSRF. The account-metadata file (accounts.json) is written with user-only file permissions. Cesium Events has no servers of its own. There is no central place where an attacker could compromise data across users.

Children's privacy

Cesium Events does not knowingly collect personal information from anyone, including children under 13. The app stores only what you explicitly connect (calendar accounts) and your local preferences. It is safe for use by individuals of all ages.

Changes to this policy

If this policy changes, the "Last updated" date at the top will change too. Material changes will be highlighted on the Cesium Events page on this site.

Your rights

You can disconnect any account from inside Cesium Events at any time. Doing so deletes the local OAuth tokens, the calendar-list cache, and the account row in accounts.json. You can also revoke access externally via the Google or Microsoft account pages linked above. Uninstalling Cesium Events removes all locally stored preferences, tokens, caches, and account metadata.

Compliance

Cesium Events' data-handling practices are designed to comply with applicable privacy laws including the GDPR (EU) and CCPA (California). Because Cesium Events collects no personal data on Jucius Labs's behalf (your calendar data flows from Google or Microsoft directly to your Mac, and never to us), most provisions of these regulations do not apply, but we honor the principles regardless.

Contact

Questions about this policy: privacy@jucius.com

General support: inquiries@jucius.com

Site: jucius.com