> ## Documentation Index
> Fetch the complete documentation index at: https://docs.runflow.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Outpaint (Expand)

> Expand the canvas of an image with AI-generated content that matches the existing scene. Specify percent expand on each side - required so the customer is intentional.

<Info>
  Pricing: **\$0.55/request**. Endpoint: `POST /v1/models/runflow/outpaint/runs`.
</Info>

Expand the canvas of an image with AI-generated content that matches the existing scene. Specify percent expand on each side - required so the customer is intentional.

## Overview

* **Endpoint**: [https://api.runflow.io/v1/models/runflow/outpaint/runs](https://api.runflow.io/v1/models/runflow/outpaint/runs)
* **Model ID**: runflow/outpaint
* **Provider**: Runflow
* **License**: commercial
* **Last Updated**: 2026-04-28

## Pricing

* **Base price**: \$0.55/request
* **Note**: Per image - outpainting / canvas expand

# Outpaint (Expand) API

**Endpoint:** `POST /v1/models/runflow/outpaint/runs`

## Run the model

### Python

```python theme={"dark"}
import requests

response = requests.post(
    "https://api.runflow.io/v1/models/runflow/outpaint/runs",
    headers={"Authorization": "Bearer RUNFLOW_API_KEY"},
    json={
        "input": {
            "image_url": "https://public.runflow.io/images/models/runflow/outpaint/examples/1/before.webp",
            "expand_top": 10,
            "expand_left": 70,
            "expand_right": 0,
            "expand_bottom": 30
        },
        "callback_url": "https://your-server.com/webhook"
    },
)

data = response.json()
print(data)
```

### Node.js

```javascript theme={"dark"}
const response = await fetch(
  "https://api.runflow.io/v1/models/runflow/outpaint/runs",
  {
    method: "POST",
    headers: {
      "Authorization": "Bearer RUNFLOW_API_KEY",
      "Content-Type": "application/json",
    },
    body: JSON.stringify({
        "input": {
            "image_url": "https://public.runflow.io/images/models/runflow/outpaint/examples/1/before.webp",
            "expand_top": 10,
            "expand_left": 70,
            "expand_right": 0,
            "expand_bottom": 30
        },
        "callback_url": "https://your-server.com/webhook"
    }),
  }
);

const data = await response.json();
console.log(data);
```

### cURL

```bash theme={"dark"}
curl -X POST https://api.runflow.io/v1/models/runflow/outpaint/runs \
  -H "Authorization: Bearer $RUNFLOW_API_KEY" \
  -H "Content-Type: application/json" \
  --data-binary @- <<'JSON'
{
    "input": {
        "image_url": "https://public.runflow.io/images/models/runflow/outpaint/examples/1/before.webp",
        "expand_top": 10,
        "expand_left": 70,
        "expand_right": 0,
        "expand_bottom": 30
    },
    "callback_url": "https://your-server.com/webhook"
}
JSON
```

## Request parameters

| Parameter      | Type           | Required | Description                                                 |
| -------------- | -------------- | -------- | ----------------------------------------------------------- |
| `input`        | object         | required | Model input parameters. See "Input schema" below.           |
| `callback_url` | string \| null | optional | Webhook URL - POSTed when the run reaches a terminal state. |
| `metadata`     | object \| null | optional | Arbitrary key-value pairs attached to the run.              |

## Input schema

| Field           | Type    | Required | Allowed values | Description                                  |
| --------------- | ------- | -------- | -------------- | -------------------------------------------- |
| `image_url`     | image   | required | Any            | URL of the image to process. HTTPS required. |
| `expand_top`    | integer | required | Any            | 0–80% expand on the top edge.                |
| `expand_bottom` | integer | required | Any            | 0–80% expand on the bottom edge.             |
| `expand_left`   | integer | required | Any            | 0–80% expand on the left edge.               |
| `expand_right`  | integer | required | Any            | 0–80% expand on the right edge.              |

## Output schema

| Field           | Type | Description                                                |
| --------------- | ---- | ---------------------------------------------------------- |
| `outputs`       | json | Array of result items, each with at minimum a `url` field. |
| `seed`          | json | Random seed used (null if N/A).                            |
| `timing`        | json | Provider timing breakdown (null if not surfaced).          |
| `nsfw_detected` | json | Provider NSFW flag (null if not surfaced).                 |

## Callback payload

When you provide a `callback_url`, Runflow POSTs to it once the run reaches a terminal state.

| Field          | Type           | Description                                                    |
| -------------- | -------------- | -------------------------------------------------------------- |
| `event`        | string         | Event type: "run.completed", "run.failed", or "run.cancelled". |
| `run_id`       | string         | The unique identifier of the run.                              |
| `status`       | string         | Terminal status: "succeeded", "failed", or "cancelled".        |
| `output`       | object \| null | The run output. Null if the run failed or was cancelled.       |
| `duration_ms`  | number \| null | Total run duration in milliseconds.                            |
| `created_at`   | string \| null | ISO 8601 timestamp when the run was created.                   |
| `completed_at` | string \| null | ISO 8601 timestamp when the run reached terminal state.        |
| `metadata`     | object \| null | The metadata object passed at run creation, if any.            |

* **Retries:** 3 attempts with exponential backoff (1s, 2s). Retries on 5xx / network errors only.
* **Headers:** `Runflow-Request-Id` is always sent. `Runflow-Signature` is sent if a signing secret is configured.

## Additional Resources

* [Playground](https://app.runflow.io/models/runflow/outpaint)
* [API Reference](https://app.runflow.io/models/runflow/outpaint?tab=api)
* [Documentation](https://docs.runflow.io)
* [OpenAPI](https://docs.runflow.io/api/openapi.public.json)

## Related

<CardGroup cols={2}>
  <Card title="Browse all models" icon="grid" href="/models">Browse the catalog.</Card>
  <Card title="Run lifecycle" icon="play" href="/concepts/runs">Callbacks, polling, statuses.</Card>
  <Card title="Callbacks" icon="webhook" href="/concepts/callbacks">Handle async results.</Card>
  <Card title="Pricing" icon="coin" href="/concepts/pricing">How requests bill out.</Card>
</CardGroup>