Introduction

Ablauf is a durable workflow engine for Cloudflare Workers, powered by Durable Objects. It lets you write workflows that survive restarts, failures, and deployments—without setting up external queues, state machines, or orchestration services.

Why Ablauf?

Traditional workflow engines require complex infrastructure: message queues, state stores, worker pools. Ablauf brings durable execution to the edge with zero external dependencies.

Here's what you get:

• Replay-based execution: Workflows automatically resume after restarts. Completed steps return cached results from SQLite.
• Automatic retries: Steps fail? They retry with exponential backoff. You control the limits.
• Typed events: Wait for external events with full TypeScript safety and Zod validation.
• Real-time updates: Stream workflow progress to clients via Server-Sent Events.
• Edge-native: Runs on Cloudflare Workers. Your workflows live close to your users.

Quick Example

Here's a workflow that processes a payment with retries, waits for confirmation, and sends a receipt:

import { defineWorkflow } from '@der-ablauf/workflows';

const PaymentWorkflow = defineWorkflow((t) => ({
	type: 'payment',
	input: t.object({
		orderId: t.string(),
		amount: t.number(),
	}),
	events: {
		confirmed: t.object({ transactionId: t.string() }),
	},
	run: async (step, payload) => {
		// This step retries on failure
		const charge = await step.do('charge-card', async () => {
			return await stripe.charges.create({
				amount: payload.amount,
				currency: 'usd',
			});
		});

		// Wait for external confirmation (webhook, user action, etc.)
		const confirmation = await step.waitForEvent('confirmed', {
			timeout: '5m',
		});

		// Send receipt
		await step.do('send-receipt', async () => {
			await sendEmail({
				to: payload.orderId,
				subject: 'Payment received!',
				transactionId: confirmation.transactionId,
			});
		});

		return { status: 'complete', charge };
	},
}));

If the worker crashes after charging the card, Ablauf replays the workflow. The charge-card step returns the cached result—your customer won't be charged twice. The workflow picks up where it left off.

How It Works

Ablauf uses replay-based execution. Every time a workflow wakes up (on a new request, after a timer, or when an event arrives), it:

1. Replays from the beginning
2. Returns cached results for completed steps
3. Executes new steps and persists them to SQLite
4. Resumes from the next step

This model is simple, predictable, and correct. No manual state management. No race conditions.

Built on Cloudflare

Ablauf is designed for Cloudflare Workers and Durable Objects:

• Durable Objects provide consistent SQLite storage and automatic failover
• Edge deployment means low latency worldwide
• No external dependencies—no queues, no databases, no orchestrators

You bring Hono (or any Worker-compatible framework), define your workflows, and deploy. That's it.

What's Next?

Ready to build? Head to Getting Started to create your first workflow.

Want to dive deeper? Check out:

• Defining Workflows — Learn how to define workflows with defineWorkflow()
• Steps — Master step.do(), step.sleep(), step.sleepUntil(), and step.waitForEvent()
• Events — Send typed events to running workflows
• Dashboard — Monitor and debug your workflows in real-time
• Performance Benchmarks — Compare Ablauf vs native Cloudflare workflow execution

Fun fact: "Ablauf" is German for "process" or "sequence". It's pronounced AH-blowf. Now you know.