> ## 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.

# Smart Resize

> Resize an image to a target aspect ratio + resolution (1K, 2K, 4K) without distortion or cropping. Uses generative reframing to recompose the subject into the new frame.

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

Resize an image to a target aspect ratio + resolution (1K, 2K, 4K) without distortion or cropping. Uses generative reframing to recompose the subject into the new frame.

## Overview

* **Endpoint**: [https://api.runflow.io/v1/models/runflow/smart-resize/runs](https://api.runflow.io/v1/models/runflow/smart-resize/runs)
* **Model ID**: runflow/smart-resize
* **Provider**: Runflow
* **License**: commercial
* **Last Updated**: 2026-05-03

## Pricing

* **Base price**: \$0.55/request
* **Note**: Per image - smart resize (aspect ratio + resolution)

# Smart Resize API

**Endpoint:** `POST /v1/models/runflow/smart-resize/runs`

## Run the model

### Python

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

response = requests.post(
    "https://api.runflow.io/v1/models/runflow/smart-resize/runs",
    headers={"Authorization": "Bearer RUNFLOW_API_KEY"},
    json={
        "input": {
            "image_url": "https://public.runflow.io/images/models/runflow/smart-resize/examples/6/before.png",
            "resolution": "1K",
            "aspect_ratio": "4:3"
        },
        "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/smart-resize/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/smart-resize/examples/6/before.png",
            "resolution": "1K",
            "aspect_ratio": "4:3"
        },
        "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/smart-resize/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/smart-resize/examples/6/before.png",
        "resolution": "1K",
        "aspect_ratio": "4:3"
    },
    "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 inputs to process - typically a `.zip` produced by the frontend. bg-brain downloads it to /tmp/inputs/ and unzips with filenames preserved. HTTPS required. |
| `aspect_ratio` | string | required | Any              | Target output aspect ratio. Examples: "1:1" (square), "16:9" (widescreen), "9:16" (portrait), "4:3", "3:4", "21:9" (cinematic), "2:3", "3:2".                          |
| `resolution`   | string | required | `1K`, `2K`, `4K` | Target output resolution tier. "1K" ≈ 1024px, "2K" ≈ 2048px, "4K" ≈ 4096px on the long side.                                                                           |

## 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/smart-resize)
* [API Reference](https://app.runflow.io/models/runflow/smart-resize?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>