EventKit — Calendar & Reminders

Create, read, and manage calendar events and reminders. Covers authorization,

event and reminder CRUD, recurrence rules, alarms, and EventKitUI editors.

Targets Swift 6.2 / iOS 26+.

Contents

• [Setup](#setup)

• [Authorization](#authorization)

• [Creating Events](#creating-events)

• [Fetching Events](#fetching-events)

• [Reminders](#reminders)

• [Recurrence Rules](#recurrence-rules)

• [Alarms](#alarms)

• [EventKitUI Controllers](#eventkitui-controllers)

• [Observing Changes](#observing-changes)

• [Common Mistakes](#common-mistakes)

• [Review Checklist](#review-checklist)

• [References](#references)

Setup

Info.plist Keys

Add the required usage description strings based on what access level you need:

Key

Access Level

NSCalendarsFullAccessUsageDescription

Read + write events

NSCalendarsWriteOnlyAccessUsageDescription

Write-only events (iOS 17+)

NSRemindersFullAccessUsageDescription

Read + write reminders

For apps also targeting iOS 16 or earlier, also include the legacy NSCalendarsUsageDescription / NSRemindersUsageDescription keys.

Event Store

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

different event stores.

import EventKit

let eventStore = EKEventStore()

Authorization

iOS 17+ introduced granular access levels. Use the modern async methods.

Full Access to Events

func requestCalendarAccess() async throws -> Bool {

    let granted = try await eventStore.requestFullAccessToEvents()

    return granted

}

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.

func requestWriteAccess() async throws -> Bool {

    let granted = try await eventStore.requestWriteOnlyAccessToEvents()

    return granted

}

Full Access to Reminders

func requestRemindersAccess() async throws -> Bool {

    let granted = try await eventStore.requestFullAccessToReminders()

    return granted

}

Checking Authorization Status

let status = EKEventStore.authorizationStatus(for: .event)

switch status {

case .notDetermined:

    // Request access

    break

case .fullAccess:

    // Read and write allowed

    break

case .writeOnly:

    // Write-only access granted (iOS 17+)

    break

case .restricted:

    // Parental controls or MDM restriction

    break

case .denied:

    // User denied -- direct to Settings

    break

@unknown default:

    break

}

Creating Events

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

// List writable calendars

let calendars = eventStore.calendars(for: .event)

    .filter { $0.allowsContentModifications }

// Use the first writable calendar, or the default

let targetCalendar = calendars.first ?? eventStore.defaultCalendarForNewEvents

event.calendar = targetCalendar

Adding Structured Location

import CoreLocation

let location = EKStructuredLocation(title: "Apple Park")

location.geoLocation = CLLocation(latitude: 37.3349, longitude: -122.0090)

event.structuredLocation = location

Fetching Events

Use a date-range predicate to query events. The events(matching:) method

returns occurrences of recurring events expanded within the range.

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

if let event = eventStore.event(withIdentifier: savedEventID) {

    print(event.title ?? "No title")

}

Reminders

Creating a Reminder

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.

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

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

// Every week, indefinitely

let weeklyRule = EKRecurrenceRule(

    recurrenceWith: .weekly,

    interval: 1,

    end: nil

)

event.addRecurrenceRule(weeklyRule)

// Every 2 weeks, ending after 10 occurrences

let biweeklyRule = EKRecurrenceRule(

    recurrenceWith: .weekly,

    interval: 2,

    end: EKRecurrenceEnd(occurrenceCount: 10)

)

// Monthly, ending on a specific date

let monthlyRule = EKRecurrenceRule(

    recurrenceWith: .monthly,

    interval: 1,

    end: EKRecurrenceEnd(end: endDate)

)

Complex Recurrence

// Every Monday and Wednesday

let 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:

// Change only this occurrence

try eventStore.save(event, span: .thisEvent)

// Change this and all future occurrences

try eventStore.save(event, span: .futureEvents)

Alarms

Attach alarms to events or reminders to trigger notifications.

// 15 minutes before

let alarm = EKAlarm(relativeOffset: -15 * 60)

event.addAlarm(alarm)

// At an absolute date

let absoluteAlarm = EKAlarm(absoluteDate: alertDate)

event.addAlarm(absoluteAlarm)

EventKitUI Controllers

EKEventEditViewController — Create/Edit Events

Present the system event editor for creating or editing events.

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

import EventKitUI

let viewer = EKEventViewController()

viewer.event = existingEvent

viewer.allowsEditing = true

navigationController?.pushViewController(viewer, animated: true)

EKCalendarChooser — Select Calendars

let chooser = EKCalendarChooser(

    selectionStyle: .multiple,

    displayStyle: .allCalendars,

    entityType: .event,

    eventStore: eventStore

)

chooser.showsDoneButton = true

chooser.showsCancelButton = true

chooser.delegate = self

present(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).

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 objects may be stale.

Common Mistakes

DON'T: Use the deprecated requestAccess(to:) method

// WRONG: Deprecated in iOS 17

eventStore.requestAccess(to: .event) { granted, error in }

// CORRECT: Use the granular async methods

let granted = try await eventStore.requestFullAccessToEvents()

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

// WRONG: No check -- will throw if calendar is read-only

event.calendar = someCalendar

try eventStore.save(event, span: .thisEvent)

// CORRECT: Verify the calendar allows modifications

guard someCalendar.allowsContentModifications else {

    event.calendar = eventStore.defaultCalendarForNewEvents

    return

}

event.calendar = someCalendar

try eventStore.save(event, span: .thisEvent)

DON'T: Ignore timezone when creating events

// WRONG: Event appears at wrong time for traveling users

event.startDate = Date()

event.endDate = Date().addingTimeInterval(3600)

// CORRECT: Set the timezone explicitly for location-specific events

event.timeZone = TimeZone(identifier: "America/New_York")

event.startDate = startDate

event.endDate = endDate

DON'T: Forget to commit batched saves

// WRONG: Changes never persisted

try eventStore.save(event1, span: .thisEvent, commit: false)

try eventStore.save(event2, span: .thisEvent, commit: false)

// Missing commit!

// CORRECT: Commit after batching

try 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

// WRONG: Event fetched from storeA, saved to storeB

let event = storeA.event(withIdentifier: id)!

try storeB.save(event, span: .thisEvent) // Undefined behavior

// CORRECT: Use the same store throughout

let event = eventStore.event(withIdentifier: id)!

try eventStore.save(event, span: .thisEvent)

Review Checklist

• Correct Info.plist usage description keys added for calendars and/or reminders

• Authorization requested with iOS 17+ granular methods (requestFullAccessToEvents, requestWriteOnlyAccessToEvents, requestFullAccessToReminders)

• Authorization status checked before fetching or saving

• Single EKEventStore instance reused across the app

• Events saved to a writable calendar (allowsContentModifications checked)

• Recurring event saves specify correct EKSpan (.thisEvent vs .futureEvents)

• Batched saves followed by explicit commit()

• EKEventStoreChanged notification observed to refresh stale data

• Timezone set explicitly for location-specific events

• EKObjects not shared across different event store instances

• EventKitUI delegates dismiss controllers in completion callbacks

References

• Extended patterns (SwiftUI wrappers, predicate queries, batch operations): references/eventkit-patterns.md

• EventKit framework

• EKEventStore

• EKEvent

• EKReminder

• EKRecurrenceRule

• EKCalendar

• EventKit UI

• EKEventEditViewController

• EKCalendarChooser

• Accessing the event store

• Creating a recurring event