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+---
+name: cloudflare-workflows
+description: |
+  Build durable workflows with Cloudflare Workflows (GA April 2025). Features step.do, step.sleep, waitForEvent,
+  Vitest testing, and runs for hours to days with automatic retries and state persistence.
+
+  Use when: creating long-running workflows, implementing retry logic, building event-driven processes,
+  testing workflows with cloudflare:test, coordinating API calls, or troubleshooting NonRetryableError,
+  I/O context errors, serialization failures.
+
+  Keywords: cloudflare workflows, workflows workers, durable execution, workflow step,
+  WorkflowEntrypoint, step.do, step.sleep, workflow retries, NonRetryableError,
+  workflow state, wrangler workflows, workflow events, long-running tasks, step.sleepUntil,
+  step.waitForEvent, workflow bindings, vitest testing, cloudflare:test, introspectWorkflowInstance
+license: MIT
+---
+
+# Cloudflare Workflows
+
+**Status**: Production Ready ✅ (GA since April 2025)
+**Last Updated**: 2025-11-25
+**Dependencies**: cloudflare-worker-base (for Worker setup)
+**Latest Versions**: wrangler@4.50.0, @cloudflare/workers-types@4.20251121.0
+
+**Recent Updates (2025)**:
+- **April 2025**: Workflows GA release - waitForEvent API, Vitest testing, CPU time metrics, 4,500 concurrent instances
+- **October 2025**: Instance creation rate 10x faster (100/sec), concurrency increased to 10,000
+- **2025 Limits**: Max steps 1,024, state persistence 1MB/step (100MB-1GB per instance), event payloads 1MB, CPU time 5 min max
+- **Testing**: cloudflare:test module with introspectWorkflowInstance, disableSleeps, mockStepResult, mockEvent modifiers
+- **Platform**: Waiting instances don't count toward concurrency, retention 3-30 days, subrequests 50-1,000
+
+---
+
+## Quick Start (5 Minutes)
+
+```bash
+# 1. Scaffold project
+npm create cloudflare@latest my-workflow -- --template cloudflare/workflows-starter --git --deploy false
+cd my-workflow
+
+# 2. Configure wrangler.jsonc
+{
+  "name": "my-workflow",
+  "main": "src/index.ts",
+  "compatibility_date": "2025-11-25",
+  "workflows": [{
+    "name": "my-workflow",
+    "binding": "MY_WORKFLOW",
+    "class_name": "MyWorkflow"
+  }]
+}
+
+# 3. Create workflow (src/index.ts)
+import { WorkflowEntrypoint, WorkflowStep, WorkflowEvent } from 'cloudflare:workers';
+
+export class MyWorkflow extends WorkflowEntrypoint<Env, Params> {
+  async run(event: WorkflowEvent<Params>, step: WorkflowStep) {
+    const result = await step.do('process', async () => { /* work */ });
+    await step.sleep('wait', '1 hour');
+    await step.do('continue', async () => { /* more work */ });
+  }
+}
+
+# 4. Deploy and test
+npm run deploy
+npx wrangler workflows instances list my-workflow
+```
+
+**CRITICAL**: Extends `WorkflowEntrypoint`, implements `run()` with `step` methods, bindings in wrangler.jsonc
+
+---
+
+
+## Step Methods
+
+### step.do() - Execute Work
+
+```typescript
+step.do<T>(name: string, config?: WorkflowStepConfig, callback: () => Promise<T>): Promise<T>
+```
+
+**Parameters:**
+- `name` - Step name (for observability)
+- `config` (optional) - Retry configuration (retries, timeout, backoff)
+- `callback` - Async function that does the work
+
+**Returns:** Value from callback (must be serializable)
+
+**Example:**
+```typescript
+const result = await step.do('call API', { retries: { limit: 10, delay: '10s', backoff: 'exponential' }, timeout: '5 min' }, async () => {
+  return await fetch('https://api.example.com/data').then(r => r.json());
+});
+```
+
+**CRITICAL - Serialization:**
+- ✅ Allowed: string, number, boolean, Array, Object, null
+- ❌ Forbidden: Function, Symbol, circular references, undefined
+- Throws error if return value isn't JSON serializable
+
+---
+
+### step.sleep() - Relative Sleep
+
+```typescript
+step.sleep(name: string, duration: WorkflowDuration): Promise<void>
+```
+
+**Parameters:**
+- `name` - Step name
+- `duration` - Number (ms) or string: `"second"`, `"minute"`, `"hour"`, `"day"`, `"week"`, `"month"`, `"year"` (plural forms accepted)
+
+**Examples:**
+```typescript
+await step.sleep('wait 5 minutes', '5 minutes');
+await step.sleep('wait 1 hour', '1 hour');
+await step.sleep('wait 2 days', '2 days');
+await step.sleep('wait 30 seconds', 30000);  // milliseconds
+```
+
+**Note:** Resuming workflows take priority over new instances. Sleeps don't count toward step limits.
+
+---
+
+### step.sleepUntil() - Sleep to Specific Date
+
+```typescript
+step.sleepUntil(name: string, timestamp: Date | number): Promise<void>
+```
+
+**Parameters:**
+- `name` - Step name
+- `timestamp` - Date object or UNIX timestamp (milliseconds)
+
+**Examples:**
+```typescript
+await step.sleepUntil('wait for launch', new Date('2025-12-25T00:00:00Z'));
+await step.sleepUntil('wait until time', Date.parse('24 Oct 2024 13:00:00 UTC'));
+```
+
+---
+
+### step.waitForEvent() - Wait for External Event (GA April 2025)
+
+```typescript
+step.waitForEvent<T>(name: string, options: { type: string; timeout?: string | number }): Promise<T>
+```
+
+**Parameters:**
+- `name` - Step name
+- `options.type` - Event type to match
+- `options.timeout` (optional) - Max wait time (default: 24 hours, max: 30 days)
+
+**Returns:** Event payload sent via `instance.sendEvent()`
+
+**Example:**
+```typescript
+export class PaymentWorkflow extends WorkflowEntrypoint<Env, Params> {
+  async run(event: WorkflowEvent<Params>, step: WorkflowStep) {
+    await step.do('create payment', async () => { /* Stripe API */ });
+
+    const webhookData = await step.waitForEvent<StripeWebhook>(
+      'wait for payment confirmation',
+      { type: 'stripe-webhook', timeout: '1 hour' }
+    );
+
+    if (webhookData.status === 'succeeded') {
+      await step.do('fulfill order', async () => { /* fulfill */ });
+    }
+  }
+}
+
+// Worker sends event to workflow
+export default {
+  async fetch(req: Request, env: Env): Promise<Response> {
+    if (req.url.includes('/webhook/stripe')) {
+      const instance = await env.PAYMENT_WORKFLOW.get(instanceId);
+      await instance.sendEvent({ type: 'stripe-webhook', payload: await req.json() });
+      return new Response('OK');
+    }
+  }
+};
+```
+
+**Timeout handling:**
+```typescript
+try {
+  const event = await step.waitForEvent('wait for user', { type: 'user-submitted', timeout: '10 minutes' });
+} catch (error) {
+  await step.do('send reminder', async () => { /* reminder */ });
+}
+```
+
+---
+
+## WorkflowStepConfig
+
+```typescript
+interface WorkflowStepConfig {
+  retries?: {
+    limit: number;          // Max attempts (Infinity allowed)
+    delay: string | number; // Delay between retries
+    backoff?: 'constant' | 'linear' | 'exponential';
+  };
+  timeout?: string | number; // Max time per attempt
+}
+```
+
+**Default:** `{ retries: { limit: 5, delay: 10000, backoff: 'exponential' }, timeout: '10 minutes' }`
+
+**Backoff Examples:**
+```typescript
+// Constant: 30s, 30s, 30s
+{ retries: { limit: 3, delay: '30 seconds', backoff: 'constant' } }
+
+// Linear: 1m, 2m, 3m, 4m, 5m
+{ retries: { limit: 5, delay: '1 minute', backoff: 'linear' } }
+
+// Exponential (recommended): 10s, 20s, 40s, 80s, 160s
+{ retries: { limit: 10, delay: '10 seconds', backoff: 'exponential' }, timeout: '5 minutes' }
+
+// Unlimited retries
+{ retries: { limit: Infinity, delay: '1 minute', backoff: 'exponential' } }
+
+// No retries
+{ retries: { limit: 0 } }
+```
+
+---
+
+## Error Handling
+
+### NonRetryableError
+
+Force workflow to fail immediately without retrying:
+
+```typescript
+import { WorkflowEntrypoint, WorkflowStep, WorkflowEvent } from 'cloudflare:workers';
+import { NonRetryableError } from 'cloudflare:workflows';
+
+export class MyWorkflow extends WorkflowEntrypoint<Env, Params> {
+  async run(event: WorkflowEvent<Params>, step: WorkflowStep) {
+    await step.do('validate input', async () => {
+      if (!event.payload.userId) {
+        throw new NonRetryableError('userId is required');
+      }
+
+      // Validate user exists
+      const user = await this.env.DB.prepare(
+        'SELECT * FROM users WHERE id = ?'
+      ).bind(event.payload.userId).first();
+
+      if (!user) {
+        // Terminal error - retrying won't help
+        throw new NonRetryableError('User not found');
+      }
+
+      return user;
+    });
+  }
+}
+```
+
+**When to use NonRetryableError:**
+- ✅ Authentication/authorization failures
+- ✅ Invalid input that won't change
+- ✅ Resource doesn't exist (404)
+- ✅ Validation errors
+- ❌ Network failures (should retry)
+- ❌ Rate limits (should retry with backoff)
+- ❌ Temporary service outages (should retry)
+
+---
+
+### Catch Errors to Continue Workflow
+
+Prevent workflow failure by catching optional step errors:
+
+```typescript
+export class MyWorkflow extends WorkflowEntrypoint<Env, Params> {
+  async run(event: WorkflowEvent<Params>, step: WorkflowStep) {
+    await step.do('process payment', async () => { /* critical */ });
+
+    try {
+      await step.do('send email', async () => { /* optional */ });
+    } catch (error) {
+      await step.do('log failure', async () => {
+        await this.env.DB.prepare('INSERT INTO failed_emails VALUES (?, ?)').bind(event.payload.userId, error.message).run();
+      });
+    }
+
+    await step.do('update status', async () => { /* continues */ });
+  }
+}
+```
+
+**Graceful Degradation:**
+```typescript
+let result;
+try {
+  result = await step.do('call primary API', async () => await callPrimaryAPI());
+} catch {
+  result = await step.do('call backup API', async () => await callBackupAPI());
+}
+```
+
+---
+
+## Triggering Workflows
+
+**Configure binding (wrangler.jsonc):**
+```jsonc
+{
+  "workflows": [{
+    "name": "my-workflow",
+    "binding": "MY_WORKFLOW",
+    "class_name": "MyWorkflow",
+    "script_name": "workflow-worker"  // If workflow in different Worker
+  }]
+}
+```
+
+**Trigger from Worker:**
+```typescript
+const instance = await env.MY_WORKFLOW.create({ params: { userId: '123' } });
+return Response.json({ id: instance.id, status: await instance.status() });
+```
+
+**Instance Management:**
+```typescript
+const instance = await env.MY_WORKFLOW.get(instanceId);
+const status = await instance.status();  // { status: 'running'|'complete'|'errored'|'queued', error, output }
+await instance.sendEvent({ type: 'user-action', payload: { action: 'approved' } });
+await instance.pause();
+await instance.resume();
+await instance.terminate();
+```
+
+---
+
+
+## State Persistence
+
+Workflows automatically persist state returned from `step.do()`:
+
+**✅ Serializable:**
+- Primitives: `string`, `number`, `boolean`, `null`
+- Arrays, Objects, Nested structures
+
+**❌ Non-Serializable:**
+- Functions, Symbols, circular references, undefined, class instances
+
+**Example:**
+```typescript
+// ✅ Good
+const result = await step.do('fetch data', async () => ({
+  users: [{ id: 1, name: 'Alice' }],
+  timestamp: Date.now(),
+  metadata: null
+}));
+
+// ❌ Bad - function not serializable
+const bad = await step.do('bad', async () => ({ data: [1, 2, 3], transform: (x) => x * 2 }));  // Throws error!
+```
+
+**Access State Across Steps:**
+```typescript
+const userData = await step.do('fetch user', async () => ({ id: 123, email: 'user@example.com' }));
+const orderData = await step.do('create order', async () => ({ userId: userData.id, orderId: 'ORD-456' }));
+await step.do('send email', async () => sendEmail({ to: userData.email, subject: `Order ${orderData.orderId}` }));
+```
+
+---
+
+## Observability
+
+### Built-in Metrics (Enhanced in 2025)
+
+Workflows automatically track:
+- **Instance status**: queued, running, complete, errored, paused, waiting
+- **Step execution**: start/end times, duration, success/failure
+- **Retry history**: attempts, errors, delays
+- **Sleep state**: when workflow will wake up
+- **Output**: return values from steps and run()
+- **CPU time** (GA April 2025): Active processing time per instance for billing insights
+
+### View Metrics in Dashboard
+
+Access via Cloudflare dashboard:
+1. Workers & Pages
+2. Select your workflow
+3. View instances and metrics
+
+**Metrics include:**
+- Total instances created
+- Success/error rates
+- Average execution time
+- Step-level performance
+- **CPU time consumption** (2025 feature)
+
+### Programmatic Access
+
+```typescript
+const instance = await env.MY_WORKFLOW.get(instanceId);
+const status = await instance.status();
+
+console.log(status);
+// {
+//   status: 'complete' | 'running' | 'errored' | 'queued' | 'waiting' | 'unknown',
+//   error: string | null,
+//   output: { userId: '123', status: 'processed' }
+// }
+```
+
+**CPU Time Configuration (2025):**
+```jsonc
+// wrangler.jsonc
+{ "limits": { "cpu_ms": 300000 } }  // 5 minutes max (default: 30 seconds)
+```
+
+---
+
+## Limits (Updated 2025)
+
+| Feature | Workers Free | Workers Paid |
+|---------|--------------|--------------|
+| **Max steps per workflow** | 1,024 | 1,024 |
+| **Max state per step** | 1 MiB | 1 MiB |
+| **Max state per instance** | 100 MB | 1 GB |
+| **Max event payload size** | 1 MiB | 1 MiB |
+| **Max sleep/sleepUntil duration** | 365 days | 365 days |
+| **Max waitForEvent timeout** | 365 days | 365 days |
+| **CPU time per step** | 10 ms | 30 sec (default), 5 min (max) |
+| **Duration (wall clock) per step** | Unlimited | Unlimited |
+| **Max workflow executions** | 100,000/day | Unlimited |
+| **Concurrent instances** | 25 | 10,000 (Oct 2025, up from 4,500) |
+| **Instance creation rate** | 100/second | 100/second (Oct 2025, 10x faster) |
+| **Max queued instances** | 100,000 | 1,000,000 |
+| **Max subrequests per instance** | 50/request | 1,000/request |
+| **Retention (completed state)** | 3 days | 30 days |
+| **Max Workflow name length** | 64 chars | 64 chars |
+| **Max instance ID length** | 100 chars | 100 chars |
+
+**CRITICAL Notes:**
+- `step.sleep()` and `step.sleepUntil()` do NOT count toward 1,024 step limit
+- **Waiting instances** (sleeping, retrying, or waiting for events) do NOT count toward concurrency limits
+- Instance creation rate increased 10x (October 2025): 100 per 10 seconds → 100 per second
+- Max concurrency increased (October 2025): 4,500 → 10,000 concurrent instances
+- State persistence limits increased (2025): 128 KB → 1 MiB per step, 100 MB - 1 GB per instance
+- Event payload size increased (2025): 128 KB → 1 MiB
+- CPU time configurable via `wrangler.jsonc`: `{ "limits": { "cpu_ms": 300000 } }` (5 min max)
+
+---
+
+## Pricing
+
+**Requires Workers Paid plan** ($5/month)
+
+**Workflow Executions:**
+- First 10,000,000 step executions/month: **FREE**
+- After that: **$0.30 per million step executions**
+
+**What counts as a step execution:**
+- Each `step.do()` call
+- Each retry of a step
+- `step.sleep()`, `step.sleepUntil()`, `step.waitForEvent()` do NOT count
+
+**Cost examples:**
+- Workflow with 5 steps, no retries: **5 step executions**
+- Workflow with 3 steps, 1 step retries 2 times: **5 step executions** (3 + 2)
+- 10M simple workflows/month (5 steps each): ((50M - 10M) / 1M) × $0.30 = **$12/month**
+
+
+## Troubleshooting
+
+### Issue: "Cannot perform I/O on behalf of a different request"
+
+**Cause:** Trying to use I/O objects created in one request context from another request handler
+
+**Solution:** Always perform I/O within `step.do()` callbacks
+
+```typescript
+// ❌ Bad - I/O outside step
+const response = await fetch('https://api.example.com/data');
+const data = await response.json();
+
+await step.do('use data', async () => {
+  // Using data from outside step's I/O context
+  return data;  // This will fail!
+});
+
+// ✅ Good - I/O inside step
+const data = await step.do('fetch data', async () => {
+  const response = await fetch('https://api.example.com/data');
+  return await response.json();  // ✅ Correct
+});
+```
+
+---
+
+### Issue: NonRetryableError behaves differently in dev vs production
+
+**Known Issue:** Throwing NonRetryableError with empty message in dev mode causes retries, but works correctly in production
+
+**Workaround:** Always provide a message to NonRetryableError
+
+```typescript
+// ❌ May retry in dev
+throw new NonRetryableError();
+
+// ✅ Works consistently
+throw new NonRetryableError('User not found');
+```
+
+**Source:** [workers-sdk#10113](https://github.com/cloudflare/workers-sdk/issues/10113)
+
+---
+
+## Vitest Testing (GA April 2025)
+
+Workflows support full testing integration via `cloudflare:test` module.
+
+### Setup
+
+```bash
+npm install -D vitest@latest @cloudflare/vitest-pool-workers@latest
+```
+
+**vitest.config.ts:**
+```typescript
+import { defineWorkersConfig } from '@cloudflare/vitest-pool-workers/config';
+export default defineWorkersConfig({ test: { poolOptions: { workers: { miniflare: { bindings: { MY_WORKFLOW: { scriptName: 'workflow' } } } } } } });
+```
+
+### Introspection API
+
+```typescript
+import { env, introspectWorkflowInstance } from 'cloudflare:test';
+
+it('should complete workflow', async () => {
+  const instance = await introspectWorkflowInstance(env.MY_WORKFLOW, 'test-123');
+
+  try {
+    await instance.modify(async (m) => {
+      await m.disableSleeps();  // Skip all sleeps
+      await m.mockStepResult({ name: 'fetch data' }, { users: [{ id: 1 }] });  // Mock step result
+      await m.mockEvent({ type: 'approval', payload: { approved: true } });  // Send mock event
+      await m.mockStepError({ name: 'call API' }, new Error('Network timeout'), 1);  // Force error once
+    });
+
+    await env.MY_WORKFLOW.create({ id: 'test-123' });
+    await expect(instance.waitForStatus('complete')).resolves.not.toThrow();
+  } finally {
+    await instance.dispose();  // Cleanup
+  }
+});
+```
+
+### Test Modifiers
+
+- `disableSleeps(steps?)` - Skip sleeps instantly
+- `mockStepResult(step, result)` - Mock step.do() result
+- `mockStepError(step, error, times?)` - Force step.do() to throw
+- `mockEvent(event)` - Send mock event to step.waitForEvent()
+- `forceStepTimeout(step, times?)` - Force step.do() timeout
+- `forceEventTimeout(step)` - Force step.waitForEvent() timeout
+
+**Official Docs**: https://developers.cloudflare.com/workers/testing/vitest-integration/
+
+---
+
+## Related Documentation
+
+- **Cloudflare Workflows Docs**: https://developers.cloudflare.com/workflows/
+- **Get Started Guide**: https://developers.cloudflare.com/workflows/get-started/guide/
+- **Workers API**: https://developers.cloudflare.com/workflows/build/workers-api/
+- **Vitest Testing**: https://developers.cloudflare.com/workers/testing/vitest-integration/
+- **Sleeping and Retrying**: https://developers.cloudflare.com/workflows/build/sleeping-and-retrying/
+- **Events and Parameters**: https://developers.cloudflare.com/workflows/build/events-and-parameters/
+- **Limits**: https://developers.cloudflare.com/workflows/reference/limits/
+- **Pricing**: https://developers.cloudflare.com/workflows/platform/pricing/
+- **Changelog**: https://developers.cloudflare.com/workflows/reference/changelog/
+- **MCP Tool**: Use `mcp__cloudflare-docs__search_cloudflare_documentation` for latest docs
+
+---
+
+**Last Updated**: 2025-11-25
+**Version**: 1.0.0
+**Maintainer**: Jeremy Dawes | jeremy@jezweb.net