Handlers

Methods on the module Worker’s exported object.

export default {
  async fetch(
    request: Request,
    env: Env,
    ctx: ExecutionContext,
  ): Promise<Response> {
    return new Response("ok");
  },
  async scheduled(
    controller: ScheduledController,
    env: Env,
    ctx: ExecutionContext,
  ): Promise<void> {},
  async queue(
    batch: MessageBatch,
    env: Env,
    ctx: ExecutionContext,
  ): Promise<void> {},
} satisfies ExportedHandler<Env>;

Durable Object alarm() lives on the DO class, not the default export. See DO Alarms.

Compatibility

Topic	Cloudflare	open-compute
fetch, scheduled, and queue arguments and return values	Yes — Handlers	Yes
ctx.waitUntil, ctx.passThroughOnException	Yes	Follow workerd
Email handler / Tail handler	Yes	Not provided
Cron trigger	Hosted Cron	UTC five-field; misfire projects at most the latest slot in grace — Cron Triggers
Queue delivery	Global queue semantics	Single-node at-least-once, not global FIFO
triggers.crons / queue-consumer array in the project file	Wrangler	Not allowed; platform deployment metadata accepts crons and queue_consumers