---
title: Start Workflows in Background
impact: CRITICAL
impactDescription: Background workflows survive crashes and restarts
tags: workflow, background, start_workflow, handle
---

## Start Workflows in Background

Use `DBOS.start_workflow` to run workflows in the background. This returns a handle to monitor or retrieve results.

**Incorrect (using threads):**

```python
import threading

@DBOS.workflow()
def long_task(data):
    # Long running work
    pass

# Don't use threads for DBOS workflows!
thread = threading.Thread(target=long_task, args=(data,))
thread.start()
```

**Correct (using start_workflow):**

```python
from dbos import DBOS, WorkflowHandle

@DBOS.workflow()
def long_task(data):
    # Long running work
    return "done"

# Start workflow in background
handle: WorkflowHandle = DBOS.start_workflow(long_task, data)

# Later, get the result
result = handle.get_result()

# Or check status
status = handle.get_status()
```

You can retrieve a workflow handle later using its ID:

```python
# Get workflow ID
workflow_id = handle.get_workflow_id()

# Later, retrieve the handle
handle = DBOS.retrieve_workflow(workflow_id)
result = handle.get_result()
```

Reference: [Starting Workflows](https://docs.dbos.dev/python/tutorials/workflow-tutorial#starting-workflows-in-the-background)