EventKit Reference

Complete API reference for EventKit (programmatic access to the Calendar and Reminders databases) and EventKitUI (system view controllers for calendar UI). For tier-based access decisions, denial-rate framing, and pressure scenarios, see the EventKit discipline coverage in eventkit-contacts.

Platform: iOS 4.0+, iPadOS 4.0+, macOS 10.8+, Mac Catalyst 13.1+, watchOS 2.0+, visionOS 1.0+

When to Use This Reference

Use this reference when you need:

• The EKEventStore API surface (initialization, iOS 17+ authorization, calendar/source access, batch operations, change notifications)
• EKEvent and EKCalendarItem property and method reference
• EKReminder construction, EKReminderPriority, async fetch pattern
• EKAlarm configuration (relative offsets, absolute dates, structured locations)
• EKRecurrenceRule construction and frequency/end conditions
• EKCalendar and EKSource property reference and source-type filtering
• EKEventEditViewController, EKEventViewController, and EKCalendarChooser initialization and delegate methods
• Virtual conference extension setup (EKVirtualConferenceProvider)
• Siri Event Suggestions (reservation donation via Intents framework)
• Location-based reminders (EKStructuredLocation, EKAlarm.proximity)
• EKErrorDomain codes for error handling
• Platform availability for each API

Example Prompts

• "What's the iOS 17+ API for requesting write-only Calendar access?"
• "Which Info.plist keys do I need for write-only vs full access?"
• "How do I fetch reminders asynchronously, and why is the API different from events?"
• "How do I construct a recurring weekly event with an end date?"
• "How do I set a relative alarm 15 minutes before an event?"
• "How do I implement a virtual conference extension?"
• "What EKErrorDomain codes should I handle when saving an event?"
• "What's the signature for EKEventEditViewController.editViewDelegate?"

What's Covered

• EKEventStore — initialization, requestWriteOnlyAccessToEvents() / requestFullAccessToEvents() / requestFullAccessToReminders() (iOS 17+), Info.plist keys (NSCalendarsWriteOnlyAccessUsageDescription, NSCalendarsFullAccessUsageDescription, NSRemindersFullAccessUsageDescription), defaultCalendarForNewEvents, defaultCalendarForNewReminders(), source enumeration
• Event operations — save(_:span:commit:), remove(_:span:commit:), commit(), reset(), batch-save pattern
• Event fetching (synchronous) — predicateForEvents(withStart:end:calendars:), events(matching:) returns unsorted results, compareStartDate(with:) sort, run on background thread
• Reminder fetching (asynchronous) — predicateForReminders(in:), fetchReminders(matching:completion:) callback-style API, async-await bridging pattern
• Change notifications — .EKEventStoreChanged notification, refresh() on stale objects
• EKEvent — creation, title, startDate, endDate, timeZone, location, notes, URL, attendees, structured location, alarms, recurrence rules
• EKReminder — creation, dueDateComponents (NOT Date), completionDate, EKReminderPriority raw values
• EKAlarm — relative offset, absolute date, structured-location proximity (entering/leaving)
• EKRecurrenceRule — .daily, .weekly, .monthly, .yearly; interval; end conditions (EKRecurrenceEnd.occurrenceCount or .endDate); daysOfTheWeek, daysOfTheMonth, monthsOfTheYear, weeksOfTheYear
• EKCalendar and EKSource — allowsContentModifications, cgColor, type, source; EKSource.sourceType (.local, .calDAV, .exchange, .subscribed, .mobileMe, .birthdays)
• EventKitUI — EKEventEditViewController (inherits from UINavigationController — do NOT embed), EKEventViewController (inherits from UIViewController), EKCalendarChooser (displayStyle constraints under write-only access)
• Virtual conference extension — extension target setup, EKVirtualConferenceProvider, conference URL generation
• Siri Event Suggestions — INReservation donation pattern (restaurant, flight, hotel, ticketed event); zero-permission event-in-Calendar-inbox flow
• Location-based reminders — EKStructuredLocation, EKAlarm.proximity, geofencing radius
• EKErrorDomain codes — eventStoreNotAuthorized, noCalendar, noStartDate, noEndDate, datesInverted, calendarReadOnly, calendarIsImmutable, objectBelongsToDifferentStore, recurringReminderRequiresDueDate, and others
• Platform availability matrix — which APIs are available on iOS, macOS, watchOS, visionOS, and at which OS versions

Documentation Scope

This page documents the eventkit-ref skill — the API reference half of the EventKit pair.

• For the three-tier access decision, denial-rate framing, and pressure scenarios, see eventkit-contacts
• For general permission UX patterns, see privacy-ux
• For contacts framework APIs, see contacts-ref

Resources

WWDC: 2023-10052, 2020-10197

Docs: /eventkit, /eventkitui, /technotes/tn3152, /technotes/tn3153