workflow/docs/errors/timeout-in-workflow.mdx

Workflow DevKit - Build durable, resilient, and observable workflows

---
title: timeout-in-workflow
description: Use the sleep function instead of setTimeout or setInterval in workflows.
type: troubleshooting
summary: Resolve the timeout-in-workflow error by replacing setTimeout with the sleep function.
prerequisites:
  - /docs/foundations/workflows-and-steps
related:
  - /docs/api-reference/workflow/sleep
---

This error occurs when you try to use `setTimeout()`, `setInterval()`, or related timing functions directly inside a workflow function.

## Error Message

```
Timeout functions like "setTimeout" and "setInterval" are not supported in workflow functions. Use the "sleep" function from "workflow" for time-based delays.
```

## Why This Happens

Workflow functions run in a sandboxed environment where timing functions like `setTimeout()` and `setInterval()` are not available. These functions rely on asynchronous scheduling that would break the **deterministic replay** guarantees that workflows depend on.

When a workflow suspends and later resumes, it replays from the event log. If timing functions were allowed, the replay would produce different results than the original execution.

## Quick Fix

Use the `sleep` function from the `workflow` package for time-based delays. Unlike `setTimeout()`, `sleep` is tracked in the event log and replays correctly.

**Before:**

```typescript lineNumbers title="workflows/delayed.ts"
export async function delayedWorkflow() {
  "use workflow";

  // Error - setTimeout is not available in workflow functions
  await new Promise(resolve => setTimeout(resolve, 5000)); // [!code highlight]

  return 'done';
}
```

**After:**

```typescript lineNumbers title="workflows/delayed.ts"
import { sleep } from 'workflow'; // [!code highlight]

export async function delayedWorkflow() {
  "use workflow";

  // sleep is tracked in the event log and replays correctly
  await sleep('5s'); // [!code highlight]

  return 'done';
}
```

## Unavailable Functions

These timing functions cannot be used in workflow functions:

- `setTimeout()`
- `setInterval()`
- `setImmediate()`
- `clearTimeout()`
- `clearInterval()`
- `clearImmediate()`

## Common Scenarios

### Polling with Delays

If you need to poll an external service with delays between requests:

```typescript lineNumbers title="workflows/polling.ts"
import { sleep } from 'workflow';

export async function pollingWorkflow() {
  "use workflow";

  let status = 'pending';

  while (status === 'pending') {
    status = await checkStatus(); // step function
    if (status === 'pending') {
      await sleep('10s'); // [!code highlight]
    }
  }

  return status;
}

async function checkStatus() {
  "use step";
  const response = await fetch('https://api.example.com/status');
  const data = await response.json();
  return data.status;
}
```

### Scheduled Delays

For workflows that need to wait for a specific duration:

```typescript lineNumbers title="workflows/reminder.ts"
import { sleep } from 'workflow';

export async function reminderWorkflow(message: string) {
  "use workflow";

  // Wait 24 hours before sending reminder
  await sleep('24h'); // [!code highlight]

  await sendReminder(message);

  return 'reminder sent';
}

async function sendReminder(message: string) {
  "use step";
  // Send reminder logic
}
```

<Callout type="info">
The `sleep` function accepts duration strings like `'5s'`, `'10m'`, `'1h'`, `'24h'`, or milliseconds as a number. See the [sleep API reference](/docs/api-reference/workflow/sleep) for more details.
</Callout>