Cron Triggers

Cron on this platform runs the Worker’s scheduled() on UTC expressions. This is not the Cloudflare dashboard trigger UI.

export default {
  async scheduled(
    controller: ScheduledController,
    env: Env,
    ctx: ExecutionContext,
  ): Promise<void> {
    if (shouldGiveUp()) controller.noRetry();
  },
} satisfies ExportedHandler<Env>;

controller.cron is the exact string declared on the deployment. controller.scheduledTime is that logical slot’s time.

Expressions

Only five UTC fields: minute, hour, day-of-month, month, day-of-week. No seconds field, no year, no local timezone or DST.

Documented local Quartz-like extensions: * , - / L W #, plus case-insensitive three-letter month/weekday names. Weekday numbers follow the Cloudflare fixture: 1=Sunday … 7=Saturday.

Declare Worker cron triggers with standard triggers.crons. Workflow schedules remain on the standard Workflow binding and do not invoke the Worker’s scheduled() handler.

Compatibility

Topic	Cloudflare	open-compute
scheduled() handler	Yes — scheduled()	Yes
Five-field cron	Yes — Cloudflare Cron Triggers	Yes; UTC only
noRetry()	Yes	Yes
triggers.crons in the project file	Wrangler	Not allowed; deployment metadata field is crons: string[]
Misfire recovery	Hosted scheduler semantics	Projects at most the latest slot within grace; does not replay complete downtime history
Retry on known failure	Hosted policy	Configured bounded local retry unless noRetry() is called
Default misfire grace	Plan-dependent	scheduler.cron_misfire_grace_ms = 300000 (five minutes); exact values from ocd capabilities --json limits