RecurrenceTrigger | Quartz.NET

RecurrenceTrigger schedules with an iCalendar RFC 5545 recurrence rule (RRULE). Use it for patterns that CronTrigger and SimpleTrigger cannot express: "every 2nd Monday of the month", "every other week on Monday, Wednesday and Friday", "the last weekday of March each year". It takes a standard RRULE string and computes fire times lazily, without materializing all occurrences.

RRULE Basics

An RRULE is semicolon-separated key-value pairs. FREQ, the base frequency, is required; the other properties refine it:

Property	Description	Example
`FREQ`	Base frequency (required)	`YEARLY`, `MONTHLY`, `WEEKLY`, `DAILY`, `HOURLY`, `MINUTELY`, `SECONDLY`
`INTERVAL`	How often the recurrence repeats (default: 1)	`INTERVAL=2` (every other)
`COUNT`	Maximum number of times the trigger will fire	`COUNT=10`
`UNTIL`	End date/time for the recurrence	`UNTIL=20251231T235959Z`
`BYDAY`	Days of the week, optionally with ordinal	`BYDAY=MO,WE,FR` or `BYDAY=2MO` (2nd Monday)
`BYMONTHDAY`	Days of the month (1-31 or -1 to -31)	`BYMONTHDAY=15` or `BYMONTHDAY=-1` (last day)
`BYMONTH`	Months of the year (1-12)	`BYMONTH=1,6,12`
`BYSETPOS`	Position within the expanded set	`BYSETPOS=-1` (last occurrence)
`BYHOUR`	Hours (0-23)	`BYHOUR=9,17`
`BYMINUTE`	Minutes (0-59)	`BYMINUTE=0,30`
`BYSECOND`	Seconds (0-59)	`BYSECOND=0`
`BYWEEKNO`	Week numbers (1-53 or -53 to -1)	`BYWEEKNO=1,26`
`BYYEARDAY`	Day of year (1-366 or -366 to -1)	`BYYEARDAY=1,100,200`
`WKST`	Week start day (default: `MO`)	`WKST=SU`

Tips

COUNT and UNTIL are mutually exclusive - you cannot use both in the same RRULE.

Warning

COUNT counts actual firings (TimesTriggered), not recurrence occurrences, which differs from strict RFC 5545 counting:

a misfired occurrence that is skipped (e.g. by the DoNothing misfire policy) does not count;
an immediate fire caused by the misfire policy (e.g. FireAndProceed) does count.

Examples

Every 2nd Monday of the month at 9:00 AM:

ITrigger trigger = TriggerBuilder.Create()
    .WithIdentity("monthlyTrigger", "group1")
    .WithRecurrenceSchedule("FREQ=MONTHLY;BYDAY=2MO")
    .StartAt(DateBuilder.Create().InYear(2025).InMonthOnDay(1, 1).AtHourMinuteAndSecond(9, 0, 0).Build())
    .Build();

Every other week on Monday, Wednesday, and Friday:

ITrigger trigger = TriggerBuilder.Create()
    .WithIdentity("weeklyTrigger", "group1")
    .WithRecurrenceSchedule("FREQ=WEEKLY;INTERVAL=2;BYDAY=MO,WE,FR")
    .StartNow()
    .Build();

Last weekday of March each year:

ITrigger trigger = TriggerBuilder.Create()
    .WithIdentity("yearlyTrigger", "group1")
    .WithRecurrenceSchedule("FREQ=YEARLY;BYMONTH=3;BYDAY=MO,TU,WE,TH,FR;BYSETPOS=-1")
    .StartNow()
    .Build();

Every day, but only on weekdays (skip weekends):

ITrigger trigger = TriggerBuilder.Create()
    .WithIdentity("weekdayTrigger", "group1")
    .WithRecurrenceSchedule("FREQ=DAILY;BYDAY=MO,TU,WE,TH,FR")
    .StartNow()
    .Build();

Last day of every month:

ITrigger trigger = TriggerBuilder.Create()
    .WithIdentity("lastDayTrigger", "group1")
    .WithRecurrenceSchedule("FREQ=MONTHLY;BYMONTHDAY=-1")
    .StartNow()
    .Build();

Every 3 months on the 1st and 15th, limited to 10 occurrences:

ITrigger trigger = TriggerBuilder.Create()
    .WithIdentity("quarterlyTrigger", "group1")
    .WithRecurrenceSchedule("FREQ=MONTHLY;INTERVAL=3;BYMONTHDAY=1,15;COUNT=10")
    .StartNow()
    .Build();

Time Zone Support

Recurrence calculations use the system's local time zone by default. Set another with InTimeZone:

ITrigger trigger = TriggerBuilder.Create()
    .WithIdentity("trigger1", "group1")
    .WithRecurrenceSchedule("FREQ=MONTHLY;BYDAY=2MO", b => b
        .InTimeZone(TimeZones.FindById("Eastern Standard Time")))
    .StartNow()
    .Build();

DI / Hosted Service Configuration

Under AddQuartz(), use WithRecurrenceSchedule on the trigger:

services.AddQuartz(q =>
{
    q.AddJob<MyJob>(j => j.WithIdentity("myJob"));
    q.AddTrigger(t => t
        .ForJob("myJob")
        .WithIdentity("myTrigger")
        .WithRecurrenceSchedule("FREQ=MONTHLY;BYDAY=2MO")
        .StartNow());
});

RecurrenceTrigger Misfire Instructions

The RecurrenceTriggerMisfireInstruction enum has two trigger-specific instructions, with the same semantics as CronTrigger's, plus IgnoreMisfires, which every family has:

RecurrenceTriggerMisfireInstruction.FireAndProceed
RecurrenceTriggerMisfireInstruction.DoNothing
RecurrenceTriggerMisfireInstruction.IgnoreMisfires

SmartPolicy, the default, resolves to FireAndProceed.

ITrigger trigger = TriggerBuilder.Create()
    .WithIdentity("trigger1", "group1")
    .WithRecurrenceSchedule("FREQ=WEEKLY;BYDAY=MO", b => b
        .WithMisfireInstruction(RecurrenceTriggerMisfireInstruction.DoNothing))
    .Build();

When to Use RecurrenceTrigger vs Other Triggers

Scenario	Recommended Trigger
Fixed interval (every 10 seconds)	SimpleTrigger
Cron-expressible pattern (every weekday at 9am)	CronTrigger
Nth day-of-week in month (2nd Monday)	RecurrenceTrigger
Last weekday of a month	RecurrenceTrigger
Every other week on specific days	RecurrenceTrigger
Complex yearly patterns with BYSETPOS	RecurrenceTrigger
Calendar interval (every 5 months)	CalendarIntervalTrigger

Persistence

Stored in	Value
table	`QRTZ_SIMPROP_TRIGGERS` (existing; no schema change)
RRULE string	`STR_PROP_1` column, max 512 characters
trigger type discriminator	`RECUR`