Cloudflare
Workflows.

A workflow is a class with a run() method. Inside it, you call step.do() for each durable step. The name is the checkpoint key — if the workflow restarts, completed steps are skipped and their cached results returned.

# wrangler.toml
name = "order-processor"
main = "src/index.ts"

[[workflows]]
name = "order-flow"
binding = "ORDER_FLOW"
class_name = "OrderWorkflow"

Each step.do() call is an atomic unit. If it throws, the workflow retries it with configurable backoff. step.sleep() pauses the workflow for a duration without consuming compute.

import { WorkflowEntrypoint } from "cloudflare:workers";

export class OrderWorkflow extends WorkflowEntrypoint {
  async run(event, step) {
    const validated = await step.do("validate", async () => {
      return validateOrder(event.payload);
    });

    const payment = await step.do("charge", async () => {
      return chargeCard(validated);
    });

    await step.sleep("wait-for-fraud-check", "30 seconds");

    await step.do("fulfil", async () => {
      return shipOrder(payment.orderId);
    });
  }
}

Start a workflow instance from any Worker using the binding. Each instance gets a unique ID and can be queried for status.

export default {
  async fetch(req, env) {
    const order = await req.json();
    const instance = await env.ORDER_FLOW.create({
      params: order,
    });
    return Response.json({ id: instance.id });
  }
};