Eventkit

by dpearson26998d90fd121a26No license1.1K starsListed Oct 8, 2026Updated Oct 8, 2026Repository updated 2 months ago

Create, read, and manage calendar events and reminders using EventKit and EventKitUI. Use when adding events to the user's calendar, creating reminders, setting recurrence rules, requesting calendar or reminders access, presenting event editors, choosing calendars, handling alarms, observing calendar changes, or working with EKEventStore, EKEvent, EKReminder, EKCalendar, EKRecurrenceRule, EKEventEditViewController, EKCalendarChooser, or EventKitUI views.

Instructions onlySoftware Development

AI-generated overview

Guides iOS developers through EventKit and EventKitUI for calendar events, reminders, recurrence, alarms and authorization.

What it does: This skill provides reference guidance for using Apple's EventKit and EventKitUI frameworks in iOS apps. It covers authorization paths, creating and fetching events, reminders, recurrence rules, alarms, system editors such as EKEventEditViewController and EKCalendarChooser, and observing store changes. It also lists common mistakes and a review checklist, with extended patterns in a bundled reference file.
When to use it: Use it when adding calendar events or reminders to an iOS app, requesting calendar or reminders access, setting recurrence rules or alarms, presenting system event editors or calendar choosers, or observing EventKit store changes.
Requirements: Requires an iOS development context with the EventKit and EventKitUI frameworks and appropriate Info.plist usage description keys. It ships no scripts; it is instructions only, with a bundled reference document.

EventKit

Use EventKit for calendar and reminder authorization, CRUD, recurrence, alarms, and system editors.

Availability
Setup
Authorization
Creating Events
Fetching Events
Reminders
Recurrence Rules
Alarms
EventKitUI Controllers
Observing Changes
Common Mistakes
Review Checklist
References

Availability

iOS 17+: Use granular full/write-only request methods; legacy requestAccess(to:) no longer prompts and throws. The system event editor can create an event without app calendar access. For iOS 10–16, guard those APIs, use the legacy request plus NSCalendarsUsageDescription / NSRemindersUsageDescription; EventKitUI may also need NSContactsUsageDescription.
iOS 26+: The typed EKEventStore.EventStoreChanged / .changed message is available behind a guard. Keep EKEventStoreChanged for earlier systems.

Setup

Info.plist Keys

Add the usage description for the access path selected in Authorization. Do not request broader access merely to simplify the setup path.

The authorization-free system editor path needs no calendar usage string. Direct writes need write-only or full access; reads need full access. Reminders have only full access.

Event Store

Create a single EKEventStore instance and reuse it. Do not mix objects from different event stores.

Authorization

Request the narrowest access that matches the feature. Apply the versioned request path in Availability.

Key	Access Level
`NSCalendarsFullAccessUsageDescription`	Read + write events
`NSCalendarsWriteOnlyAccessUsageDescription`	Direct write-only event creation
`NSRemindersFullAccessUsageDescription`	Read + write reminders

Full Access to Events

Call try await eventStore.requestFullAccessToEvents() when the app needs to read, edit, delete, or fetch calendar events.

Write-Only Access to Events

Use when your app only creates events (e.g., saving a booking) and does not need to read existing events.

Call try await eventStore.requestWriteOnlyAccessToEvents() before direct EventKit writes that do not use EKEventEditViewController.

Write-only access can create events but cannot fetch calendars or events, including app-created events. Use full access for later query, verification, modification, or sync.

Full Access to Reminders

Call try await eventStore.requestFullAccessToReminders() before reading, creating, editing, or deleting reminders.

Checking Authorization Status

Use EKEventStore.authorizationStatus(for: .event) or .reminder before work. Handle .notDetermined, .fullAccess, .writeOnly, .restricted, .denied, and @unknown default; only .fullAccess supports event/reminder reads.

Creating Events

swift

func createEvent(    title: String,    startDate: Date,    endDate: Date,    calendar: EKCalendar? = nil) throws {    let event = EKEvent(eventStore: eventStore)    event.title = title    event.startDate = startDate    event.endDate = endDate    event.calendar = calendar ?? eventStore.defaultCalendarForNewEvents
    try eventStore.save(event, span: .thisEvent)}

func createEvent(    title: String,    startDate: Date,    endDate: Date,    calendar: EKCalendar? = nil) throws {    let event = EKEvent(eventStore: eventStore)    event.title = title    event.startDate = startDate    event.endDate = endDate    event.calendar = calendar ?? eventStore.defaultCalendarForNewEvents
    try eventStore.save(event, span: .thisEvent)}

Setting a Specific Calendar

swift

// List writable calendarslet calendars = eventStore.calendars(for: .event)    .filter { $0.allowsContentModifications }
// Use the first writable calendar, or the defaultlet targetCalendar = calendars.first ?? eventStore.defaultCalendarForNewEventsevent.calendar = targetCalendar

// List writable calendarslet calendars = eventStore.calendars(for: .event)    .filter { $0.allowsContentModifications }
// Use the first writable calendar, or the defaultlet targetCalendar = calendars.first ?? eventStore.defaultCalendarForNewEventsevent.calendar = targetCalendar

Adding Structured Location

swift

import CoreLocation
let location = EKStructuredLocation(title: "Apple Park")location.geoLocation = CLLocation(latitude: 37.3349, longitude: -122.0090)event.structuredLocation = location

import CoreLocation
let location = EKStructuredLocation(title: "Apple Park")location.geoLocation = CLLocation(latitude: 37.3349, longitude: -122.0090)event.structuredLocation = location

Fetching Events

After the full-access gate in Authorization, use a date-range predicate to query events. The events(matching:) method returns occurrences of recurring events expanded within the range. Event predicates are capped to a four-year span, and events(matching:) / enumerateEvents(matching:using:) are synchronous and return only committed events.

swift

func fetchEvents(from start: Date, to end: Date) -> [EKEvent] {    let predicate = eventStore.predicateForEvents(        withStart: start,        end: end,        calendars: nil  // nil = all calendars    )    return eventStore.events(matching: predicate)        .sorted { $0.startDate < $1.startDate }}

func fetchEvents(from start: Date, to end: Date) -> [EKEvent] {    let predicate = eventStore.predicateForEvents(        withStart: start,        end: end,        calendars: nil  // nil = all calendars    )    return eventStore.events(matching: predicate)        .sorted { $0.startDate < $1.startDate }}

Fetching a Single Event by Identifier

swift

if let event = eventStore.event(withIdentifier: savedEventID) {    print(event.title ?? "No title")}

if let event = eventStore.event(withIdentifier: savedEventID) {    print(event.title ?? "No title")}

Reminders

Creating a Reminder

swift

func createReminder(title: String, dueDate: Date) throws {    let reminder = EKReminder(eventStore: eventStore)    reminder.title = title    reminder.calendar = eventStore.defaultCalendarForNewReminders()
    let dueDateComponents = Calendar.current.dateComponents(        [.year, .month, .day, .hour, .minute],        from: dueDate    )    reminder.dueDateComponents = dueDateComponents
    try eventStore.save(reminder, commit: true)}

func createReminder(title: String, dueDate: Date) throws {    let reminder = EKReminder(eventStore: eventStore)    reminder.title = title    reminder.calendar = eventStore.defaultCalendarForNewReminders()
    let dueDateComponents = Calendar.current.dateComponents(        [.year, .month, .day, .hour, .minute],        from: dueDate    )    reminder.dueDateComponents = dueDateComponents
    try eventStore.save(reminder, commit: true)}

Fetching Reminders

Reminder fetches are asynchronous and return through a completion handler.

swift

func fetchIncompleteReminders() async -> [EKReminder] {    let predicate = eventStore.predicateForIncompleteReminders(        withDueDateStarting: nil,        ending: nil,        calendars: nil    )
    return await withCheckedContinuation { continuation in        eventStore.fetchReminders(matching: predicate) { reminders in            continuation.resume(returning: reminders ?? [])        }    }}

func fetchIncompleteReminders() async -> [EKReminder] {    let predicate = eventStore.predicateForIncompleteReminders(        withDueDateStarting: nil,        ending: nil,        calendars: nil    )
    return await withCheckedContinuation { continuation in        eventStore.fetchReminders(matching: predicate) { reminders in            continuation.resume(returning: reminders ?? [])        }    }}

Completing a Reminder

swift

func completeReminder(_ reminder: EKReminder) throws {    reminder.isCompleted = true    try eventStore.save(reminder, commit: true)}

func completeReminder(_ reminder: EKReminder) throws {    reminder.isCompleted = true    try eventStore.save(reminder, commit: true)}

Recurrence Rules

Use EKRecurrenceRule to create repeating events or reminders.

Simple Recurrence

swift

// Every week, indefinitelylet weeklyRule = EKRecurrenceRule(    recurrenceWith: .weekly,    interval: 1,    end: nil)event.addRecurrenceRule(weeklyRule)
// Every 2 weeks, ending after 10 occurrenceslet biweeklyRule = EKRecurrenceRule(    recurrenceWith: .weekly,    interval: 2,    end: EKRecurrenceEnd(occurrenceCount: 10))
// Monthly, ending on a specific datelet monthlyRule = EKRecurrenceRule(    recurrenceWith: .monthly,    interval: 1,    end: EKRecurrenceEnd(end: endDate))

// Every week, indefinitelylet weeklyRule = EKRecurrenceRule(    recurrenceWith: .weekly,    interval: 1,    end: nil)event.addRecurrenceRule(weeklyRule)
// Every 2 weeks, ending after 10 occurrenceslet biweeklyRule = EKRecurrenceRule(    recurrenceWith: .weekly,    interval: 2,    end: EKRecurrenceEnd(occurrenceCount: 10))
// Monthly, ending on a specific datelet monthlyRule = EKRecurrenceRule(    recurrenceWith: .monthly,    interval: 1,    end: EKRecurrenceEnd(end: endDate))

Complex Recurrence

swift

// Every Monday and Wednesdaylet days = [    EKRecurrenceDayOfWeek(.monday),    EKRecurrenceDayOfWeek(.wednesday)]
let complexRule = EKRecurrenceRule(    recurrenceWith: .weekly,    interval: 1,    daysOfTheWeek: days,    daysOfTheMonth: nil,    monthsOfTheYear: nil,    weeksOfTheYear: nil,    daysOfTheYear: nil,    setPositions: nil,    end: nil)event.addRecurrenceRule(complexRule)

// Every Monday and Wednesdaylet days = [    EKRecurrenceDayOfWeek(.monday),    EKRecurrenceDayOfWeek(.wednesday)]
let complexRule = EKRecurrenceRule(    recurrenceWith: .weekly,    interval: 1,    daysOfTheWeek: days,    daysOfTheMonth: nil,    monthsOfTheYear: nil,    weeksOfTheYear: nil,    daysOfTheYear: nil,    setPositions: nil,    end: nil)event.addRecurrenceRule(complexRule)

Editing Recurring Events

When saving changes to a recurring event, specify the span:

swift

// Change only this occurrencetry eventStore.save(event, span: .thisEvent)
// Change this and all future occurrencestry eventStore.save(event, span: .futureEvents)

// Change only this occurrencetry eventStore.save(event, span: .thisEvent)
// Change this and all future occurrencestry eventStore.save(event, span: .futureEvents)

Alarms

Attach alarms to events or reminders to trigger notifications.

swift

// 15 minutes beforelet alarm = EKAlarm(relativeOffset: -15 * 60)event.addAlarm(alarm)
// At an absolute datelet absoluteAlarm = EKAlarm(absoluteDate: alertDate)event.addAlarm(absoluteAlarm)

// 15 minutes beforelet alarm = EKAlarm(relativeOffset: -15 * 60)event.addAlarm(alarm)
// At an absolute datelet absoluteAlarm = EKAlarm(absoluteDate: alertDate)event.addAlarm(absoluteAlarm)

For reminder geofences, put an EKStructuredLocation and .enter / .leave proximity on an EKAlarm, then add it to the reminder. See references/eventkit-patterns.md [blocked] for the full location-based reminder pattern.

EventKitUI Controllers

EKEventEditViewController — Create/Edit Events

Present the system event editor for creating or editing events.

On the authorization-free path in Availability, the editor runs out of process with its own calendar access. Do not inspect the dismissed controller to learn what was saved; refetch only with separate full access.

swift

import EventKitUI
class EventEditorCoordinator: NSObject, EKEventEditViewDelegate {    let eventStore = EKEventStore()
    func presentEditor(from viewController: UIViewController) {        let editor = EKEventEditViewController()        editor.eventStore = eventStore        editor.editViewDelegate = self        viewController.present(editor, animated: true)    }
    func eventEditViewController(        _ controller: EKEventEditViewController,        didCompleteWith action: EKEventEditViewAction    ) {        switch action {        case .saved:            // Event saved            break        case .canceled:            break        case .deleted:            break        @unknown default:            break        }        controller.dismiss(animated: true)    }}

import EventKitUI
class EventEditorCoordinator: NSObject, EKEventEditViewDelegate {    let eventStore = EKEventStore()
    func presentEditor(from viewController: UIViewController) {        let editor = EKEventEditViewController()        editor.eventStore = eventStore        editor.editViewDelegate = self        viewController.present(editor, animated: true)    }
    func eventEditViewController(        _ controller: EKEventEditViewController,        didCompleteWith action: EKEventEditViewAction    ) {        switch action {        case .saved:            // Event saved            break        case .canceled:            break        case .deleted:            break        @unknown default:            break        }        controller.dismiss(animated: true)    }}

EKEventViewController — View an Event

swift

import EventKitUI
let viewer = EKEventViewController()viewer.event = existingEventviewer.allowsEditing = truenavigationController?.pushViewController(viewer, animated: true)

import EventKitUI
let viewer = EKEventViewController()viewer.event = existingEventviewer.allowsEditing = truenavigationController?.pushViewController(viewer, animated: true)

EKCalendarChooser — Select Calendars

EKCalendarChooser requires write-only or full calendar access. In write-only apps, the chooser behaves as writable-calendars-only and only allows a single writable calendar selection.

swift

let chooser = EKCalendarChooser(    selectionStyle: .multiple,    displayStyle: .allCalendars,    entityType: .event,    eventStore: eventStore)chooser.showsDoneButton = truechooser.showsCancelButton = truechooser.delegate = selfpresent(UINavigationController(rootViewController: chooser), animated: true)

let chooser = EKCalendarChooser(    selectionStyle: .multiple,    displayStyle: .allCalendars,    entityType: .event,    eventStore: eventStore)chooser.showsDoneButton = truechooser.showsCancelButton = truechooser.delegate = selfpresent(UINavigationController(rootViewController: chooser), animated: true)

Observing Changes

Register for EKEventStoreChanged notifications to keep your UI in sync when events are modified outside your app (e.g., by the Calendar app or a sync).

swift

NotificationCenter.default.addObserver(    forName: .EKEventStoreChanged,    object: eventStore,    queue: .main) { [weak self] _ in    self?.refreshEvents()}

NotificationCenter.default.addObserver(    forName: .EKEventStoreChanged,    object: eventStore,    queue: .main) { [weak self] _ in    self?.refreshEvents()}

Always re-fetch events after receiving this notification. Previously fetched EKEvent, EKReminder, and EKCalendar objects may be stale. The notification is posted on the main actor.

Common Mistakes

DON'T: Use legacy requestAccess(to:) on current systems

swift

// WRONG: Legacy request API on current systemseventStore.requestAccess(to: .event) { granted, error in }
// CORRECT: Use the granular async methodslet granted = try await eventStore.requestFullAccessToEvents()

// WRONG: Legacy request API on current systemseventStore.requestAccess(to: .event) { granted, error in }
// CORRECT: Use the granular async methodslet granted = try await eventStore.requestFullAccessToEvents()

Keep it only in the compatibility fallback from Availability.

DON'T: Save events to a read-only calendar

swift

// WRONG: No check -- will throw if calendar is read-onlyevent.calendar = someCalendartry eventStore.save(event, span: .thisEvent)
// CORRECT: Verify the calendar allows modificationsguard someCalendar.allowsContentModifications else {    event.calendar = eventStore.defaultCalendarForNewEvents    return}event.calendar = someCalendartry eventStore.save(event, span: .thisEvent)

// WRONG: No check -- will throw if calendar is read-onlyevent.calendar = someCalendartry eventStore.save(event, span: .thisEvent)
// CORRECT: Verify the calendar allows modificationsguard someCalendar.allowsContentModifications else {    event.calendar = eventStore.defaultCalendarForNewEvents    return}event.calendar = someCalendartry eventStore.save(event, span: .thisEvent)

DON'T: Ignore timezone when creating events

swift

// WRONG: Event appears at wrong time for traveling usersevent.startDate = Date()event.endDate = Date().addingTimeInterval(3600)
// CORRECT: Set the timezone explicitly for location-specific eventsevent.timeZone = TimeZone(identifier: "America/New_York")event.startDate = startDateevent.endDate = endDate

// WRONG: Event appears at wrong time for traveling usersevent.startDate = Date()event.endDate = Date().addingTimeInterval(3600)
// CORRECT: Set the timezone explicitly for location-specific eventsevent.timeZone = TimeZone(identifier: "America/New_York")event.startDate = startDateevent.endDate = endDate

DON'T: Forget to commit batched saves

swift

// WRONG: Changes never persistedtry eventStore.save(event1, span: .thisEvent, commit: false)try eventStore.save(event2, span: .thisEvent, commit: false)// Missing commit!
// CORRECT: Commit after batchingtry eventStore.save(event1, span: .thisEvent, commit: false)try eventStore.save(event2, span: .thisEvent, commit: false)try eventStore.commit()

// WRONG: Changes never persistedtry eventStore.save(event1, span: .thisEvent, commit: false)try eventStore.save(event2, span: .thisEvent, commit: false)// Missing commit!
// CORRECT: Commit after batchingtry eventStore.save(event1, span: .thisEvent, commit: false)try eventStore.save(event2, span: .thisEvent, commit: false)try eventStore.commit()

DON'T: Mix EKObjects from different event stores

swift

// WRONG: Event fetched from storeA, saved to storeBlet event = storeA.event(withIdentifier: id)!try storeB.save(event, span: .thisEvent) // Undefined behavior
// CORRECT: Use the same store throughoutlet event = eventStore.event(withIdentifier: id)!try eventStore.save(event, span: .thisEvent)

// WRONG: Event fetched from storeA, saved to storeBlet event = storeA.event(withIdentifier: id)!try storeB.save(event, span: .thisEvent) // Undefined behavior
// CORRECT: Use the same store throughoutlet event = eventStore.event(withIdentifier: id)!try eventStore.save(event, span: .thisEvent)

Review Checklist

References

Extended patterns (SwiftUI wrappers, predicate queries, batch operations): references/eventkit-patterns.md [blocked]
EventKit framework
EKEventStore
EKEvent
EKReminder
EKRecurrenceRule
EKCalendar
EventKit UI
EKEventEditViewController
EKCalendarChooser
Accessing the event store
Creating a recurring event

Source and attribution

Source:dpearson2699/swift-ios-skillsinskills/eventkitat commit8d90fd1

License: No license

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Eventkit

EventKit

Contents

Availability

Setup

Info.plist Keys

Event Store

Authorization

Full Access to Events

Write-Only Access to Events

Full Access to Reminders

Checking Authorization Status

Creating Events

Setting a Specific Calendar

Adding Structured Location

Fetching Events

Fetching a Single Event by Identifier

Reminders

Creating a Reminder

Fetching Reminders

Completing a Reminder

Recurrence Rules

Simple Recurrence

Complex Recurrence

Editing Recurring Events

Alarms

EventKitUI Controllers

EKEventEditViewController — Create/Edit Events

EKEventViewController — View an Event

EKCalendarChooser — Select Calendars

Observing Changes

Common Mistakes

DON'T: Use legacy requestAccess(to:) on current systems

DON'T: Save events to a read-only calendar

DON'T: Ignore timezone when creating events

DON'T: Forget to commit batched saves

DON'T: Mix EKObjects from different event stores

Review Checklist

References

Source and attribution

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