Recurring Events in Scheduler

Recurring events are appointments scheduled to repeat at regular intervals—such as daily, weekly, monthly, or yearly—based on a defined recurrence rule. These events are indicated by a repeat marker in the lower‑right corner.

Creating a recurring event

A recurring event is created by assigning a rule and RecurrenceIcon to the recurrenceRule field, which defines how often the event repeats. In the sample below, the event repeats daily and ends after five occurrences.

const schedulerData = [
            {
                Id: 1,
                Subject: 'Scrum Meeting',
                StartTime: new Date(2026, 0, 25, 11, 0),
                EndTime: new Date(2026, 0, 25, 11, 30),
                RecurringRule: 'FREQ=DAILY;INTERVAL=2;COUNT=3'
            }
        ]
        
        const eventSettings: EventSettings = {
            dataSource: schedulerData,
            fields: {
                id: 'Id',
                subject: 'Subject',
                startTime: 'StartTime',
                endTime: 'EndTime',
                recurrenceRule: 'RecurringRule'
            }
        };

const schedulerData = [
            {
                Id: 1,
                Subject: 'Scrum Meeting',
                StartTime: new Date(2026, 0, 25, 11, 0),
                EndTime: new Date(2026, 0, 25, 11, 30),
                RecurringRule: 'FREQ=DAILY;INTERVAL=2;COUNT=3'
            }
        ]
        
        const eventSettings: EventSettings = {
            dataSource: schedulerData,
            fields: {
                id: 'Id',
                subject: 'Subject',
                startTime: 'StartTime',
                endTime: 'EndTime',
                recurrenceRule: 'RecurringRule'
            }
        };

Adding exceptions to a recurring event

Specific occurrences can be excluded by adding their ISO‑formatted datetime values (without hyphens) to the recurrenceException field.

For example, 22nd February 2026 is represented as 20260222. The time portion must be provided in UTC, appended with "Z" and without spaces. For instance, 07:30:00 UTC becomes 073000Z.

const schedulerData = [
            {
                Id: 1,
                Subject: 'Scrum Meeting',
                StartTime: new Date(2026, 0, 28, 10, 0),
                EndTime: new Date(2026, 0, 28, 11, 0),
                RecurrenceRule: 'FREQ=DAILY;INTERVAL=1;COUNT=8',
                RecurrenceException: '20260129T043000Z,20260131T043000Z,20260202T043000Z'
            }
        ]
        
        const eventSettings: EventSettings = {
            dataSource: schedulerData,
            fields: {
                id: 'Id',
                subject: 'Subject',
                startTime: 'StartTime',
                endTime: 'EndTime',
                recurrenceRule: 'RecurrenceRule',
                recurrenceException: 'RecurrenceException'
            }
        };

const schedulerData = [
            {
                Id: 1,
                Subject: 'Scrum Meeting',
                StartTime: new Date(2026, 0, 28, 10, 0),
                EndTime: new Date(2026, 0, 28, 11, 0),
                RecurrenceRule: 'FREQ=DAILY;INTERVAL=1;COUNT=8',
                RecurrenceException: '20260129T043000Z,20260131T043000Z,20260202T043000Z'
            }
        ]
        
        const eventSettings: EventSettings = {
            dataSource: schedulerData,
            fields: {
                id: 'Id',
                subject: 'Subject',
                startTime: 'StartTime',
                endTime: 'EndTime',
                recurrenceRule: 'RecurrenceRule',
                recurrenceException: 'RecurrenceException'
            }
        };

Editing an occurrence in a series

To modify a single occurrence within a recurring series and display it when the Scheduler loads, add the edited occurrence as a separate event in the dataSource. Include a recurrenceID in this event and set its value to the ID of the original recurring event.

In this example, an instance occurring on 30th January 2026 is edited with different timings. Therefore, this date is excluded from the parent recurring series that runs from 28th January 2026 to 4th February 2026. This is done by adding the excluded date to the recurrenceException field of the parent event.
The modified occurrence is then added as a new event, carrying the recurrenceID field that references the parent event’s Id.

const schedulerData = [
            {
                Id: 1,
                Subject: 'Scrum Meeting',
                StartTime: new Date(2026, 0, 28, 10, 0),
                EndTime: new Date(2026, 0, 28, 11, 0),
                RecurrenceRule: 'FREQ=DAILY;INTERVAL=1;COUNT=8',
                RecurrenceException: '20260129T043000Z,20260131T043000Z,20260202T043000Z'
            },
            {
                Id: 2,
                Subject: 'Board Meeting',
                StartTime: new Date(2026, 0, 28, 12, 0),
                EndTime: new Date(2026, 0, 28, 12, 30),
                RecurrenceId: 1
            }
        ]
        
        const eventSettings: EventSettings = {
            dataSource: schedulerData,
            fields: {
                id: 'Id',
                subject: 'Subject',
                startTime: 'StartTime',
                endTime: 'EndTime',
                recurrenceRule: 'RecurrenceRule',
                recurrenceID: 'RecurrenceId'
                recurrenceException: 'RecurrenceException'
            }
        };

const schedulerData = [
            {
                Id: 1,
                Subject: 'Scrum Meeting',
                StartTime: new Date(2026, 0, 28, 10, 0),
                EndTime: new Date(2026, 0, 28, 11, 0),
                RecurrenceRule: 'FREQ=DAILY;INTERVAL=1;COUNT=8',
                RecurrenceException: '20260129T043000Z,20260131T043000Z,20260202T043000Z'
            },
            {
                Id: 2,
                Subject: 'Board Meeting',
                StartTime: new Date(2026, 0, 28, 12, 0),
                EndTime: new Date(2026, 0, 28, 12, 30),
                RecurrenceId: 1
            }
        ]
        
        const eventSettings: EventSettings = {
            dataSource: schedulerData,
            fields: {
                id: 'Id',
                subject: 'Subject',
                startTime: 'StartTime',
                endTime: 'EndTime',
                recurrenceRule: 'RecurrenceRule',
                recurrenceID: 'RecurrenceId'
                recurrenceException: 'RecurrenceException'
            }
        };

Recurrence options and rules

Events can repeat daily, weekly, monthly, or yearly using a recurrence rule. Add the following details to the recurrenceRule property to configure repeating events:

The repeat type (daily, weekly, monthly, or yearly)
The end type (count, until, or never)
The interval between occurrences
The time period during which appointments should be generated

The four repeat options are:

Recurrence Type	Description
Daily	Creates recurring instances every day.
Weekly	Creates recurring instances every week on selected days.
Monthly	Creates recurring instances each month based on selected dates or recurrence patterns.
Yearly	Creates recurring instances once a year.

Recurrence properties

The recurrence rule follows the iCalendar specification. Its properties are listed below:

Property	Purpose	Example
`FREQ`	Specifies the repeat frequency (Daily, Weekly, Monthly, Yearly).	FREQ=DAILY;INTERVAL=1
`INTERVAL`	Defines the interval between instances.	FREQ=DAILY;INTERVAL=2
`COUNT`	Specifies the total number of occurrences.	FREQ=DAILY;INTERVAL=1;COUNT=10
`UNTIL`	Indicates the end date of the recurrence series (ISO format).	FREQ=DAILY;INTERVAL=1;UNTIL=20260530T041343Z
`BYDAY`	Specifies the day(s) on which weekly recurrences occur.	FREQ=WEEKLY;INTERVAL=1;BYDAY=MO,WE
`BYMONTHDAY`	Specifies the day of the month for monthly recurrences.	FREQ=MONTHLY;BYMONTHDAY=3;INTERVAL=1
`BYMONTH`	Specifies the month index for yearly recurrences.	FREQ=YEARLY;BYMONTHDAY=16;BYMONTH=6;INTERVAL=1
`BYSETPOS`	Specifies the week index in a month (e.g., 2nd, 3rd).	FREQ=MONTHLY;BYDAY=MO;BYSETPOS=2

Daily Frequency

Description	Example
Daily recurring event that never ends	FREQ=DAILY;INTERVAL=1
Daily recurring event that ends after 5 occurrences	FREQ=DAILY;INTERVAL=1;COUNT=5
Daily recurring event that ends exactly on 12/12/2026	FREQ=DAILY;INTERVAL=1;UNTIL=20261212T041343Z
Daily event that recurs on alternate days and repeats for 10 occurrences	FREQ=DAILY;INTERVAL=2;COUNT=10
Daily recurring appointment that ends on 12/12/2026 by excluding a single occurrence on 12/10/2026	FREQ=DAILY;INTERVAL=2;UNTIL=20261212T041343Z

Weekly Frequency

Description	Example
Repeats every Monday, Wednesday, and Friday; never ends	FREQ=WEEKLY;INTERVAL=1;BYDAY=MO,WE,FR
Repeats every Thursday; ends after 10 occurrences	FREQ=WEEKLY;INTERVAL=1;BYDAY=TH;COUNT=10
Repeats every Monday; ends on 12/12/2026	FREQ=WEEKLY;INTERVAL=1;BYDAY=MO;UNTIL=20261212T041343Z
Repeats on Monday, Wednesday, and Friday on alternate weeks; ends after 10 occurrences	FREQ=WEEKLY;INTERVAL=2;BYDAY=MO,WE,FR;COUNT=10
Repeats every weekday; ends on 12/12/2026	FREQ=WEEKLY;BYDAY=MO,TU,WE,TH,FR;UNTIL=20261212T041343Z

Monthly Frequency

Description	Example
Repeats on the 15th day of each month; never ends	FREQ=MONTHLY;BYMONTHDAY=15;INTERVAL=1
Repeats on the 16th day of each month; ends after 10 occurrences	FREQ=MONTHLY;BYMONTHDAY=16;INTERVAL=1;COUNT=10
Repeats on the 17th day of each month; ends on 12/12/2026	FREQ=MONTHLY;BYMONTHDAY=17;INTERVAL=1;UNTIL=20261212T041343Z
Repeats every 2nd Friday of each month; never ends	FREQ=MONTHLY;BYDAY=FR;BYSETPOS=2;INTERVAL=1
Repeats every 4th Wednesday of each month; ends after 10 occurrences	FREQ=MONTHLY;BYDAY=WE;BYSETPOS=4;INTERVAL=1;COUNT=10
Repeats every 4th Friday of each month; ends on 12/12/2026	FREQ=MONTHLY;BYDAY=FR;BYSETPOS=4;INTERVAL=1;UNTIL=20261212T041343Z

Yearly Frequency

Description	Example
Repeats on the 15th of December every year; never ends	FREQ=YEARLY;BYMONTHDAY=15;BYMONTH=12;INTERVAL=1
Repeats on the 10th of December; ends after 10 occurrences	FREQ=YEARLY;BYMONTHDAY=10;BYMONTH=12;INTERVAL=1;COUNT=10
Repeats on the 12th of December; ends on 12/12/2026	FREQ=YEARLY;BYMONTHDAY=12;BYMONTH=12;INTERVAL=1;UNTIL=20261212T041343Z
Repeats on the 3rd Friday of December; never ends	FREQ=YEARLY;BYDAY=FR;BYMONTH=12;BYSETPOS=3;INTERVAL=1
Repeats on the 3rd Tuesday of December; ends after 10 occurrences	FREQ=YEARLY;BYDAY=TU;BYMONTH=12;BYSETPOS=3;INTERVAL=1;COUNT=10
Repeats on the 4th Wednesday of December; ends on 12/12/2026	FREQ=YEARLY;BYDAY=WE;BYMONTH=12;BYSETPOS=4;INTERVAL=1;UNTIL=20261212T041343Z

Recurrence Validation

The Scheduler includes built‑in validation during the creation, editing, dragging, and resizing of recurring appointments. The following alerts may appear:

Validation message	Description
The recurrence pattern is not valid.	This alert is raised when the selected recurrence rule is invalid. For example, if an “Until” date is chosen that occurs before the start date, an alert will appear indicating the selected pattern is invalid.
The changes made to specific instances of this series will be cancelled and those events will match the series again.	This alert appears when attempting to edit an entire series in which one or more occurrences were already modified individually. For example, if five occurrences exist and one has been edited, editing the whole series will trigger this alert.
The duration of the event must be shorter than how frequently it occurs. Shorten the duration, or change the recurrence pattern in the recurrence event editor.	This validation occurs when an event’s duration exceeds the selected repeat frequency. For example, creating a two‑day appointment with a Daily pattern (no interval) will trigger this alert.
Some months have fewer than the selected date. For these months, the occurrence will fall on the last date of the month.	This alert appears when creating a recurring appointment on the 31st of each month, since some months do not have 31 days. In such cases, the appointment moves to the last day of those months.
Two occurrences of the same event cannot occur on the same day.	This validation appears when moving or editing a single occurrence to a date where another occurrence of the same recurring series already exists.

Enhance your React apps with Syncfusion components today