> ## 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.

# FLUX Kontext

> FLUX.1 Kontext [pro] handles both text and reference images as inputs, seamlessly enabling targeted, local edits and complex transformations of entire scenes.

<Info>
  Pricing: **\$0.04/image**. Endpoint: `POST /v1/models/black-forest-labs/flux-pro/kontext/runs`.
</Info>

FLUX.1 Kontext \[pro] handles both text and reference images as inputs, seamlessly enabling targeted, local edits and complex transformations of entire scenes.

## Overview

* **Endpoint**: [https://api.runflow.io/v1/models/black-forest-labs/flux-pro/kontext/runs](https://api.runflow.io/v1/models/black-forest-labs/flux-pro/kontext/runs)
* **Model ID**: black-forest-labs/flux-pro/kontext
* **Provider**: Black Forest Labs
* **License**: commercial
* **Last Updated**: 2026-04-06

## Pricing

* **Base price**: \$0.04/image
* **Note**: \~25 runs per \$1

# FLUX Kontext API

**Endpoint:** `POST /v1/models/black-forest-labs/flux-pro/kontext/runs`

## Run the model

### Python

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

response = requests.post(
    "https://api.runflow.io/v1/models/black-forest-labs/flux-pro/kontext/runs",
    headers={"Authorization": "Bearer RUNFLOW_API_KEY"},
    json={
        "input": {
            "prompt": "Add a fluffy orange tabby cat sleeping on the desk between the two monitors, curled up on a small cushion, one paw draped over the keyboard. The cat is illuminated by the monitor glow. Everything else stays exactly the same.",
            "image_url": "https://public.runflow.io/images/models/_shared/base-engineer.png"
        },
        "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/black-forest-labs/flux-pro/kontext/runs",
  {
    method: "POST",
    headers: {
      "Authorization": "Bearer RUNFLOW_API_KEY",
      "Content-Type": "application/json",
    },
    body: JSON.stringify({
        "input": {
            "prompt": "Add a fluffy orange tabby cat sleeping on the desk between the two monitors, curled up on a small cushion, one paw draped over the keyboard. The cat is illuminated by the monitor glow. Everything else stays exactly the same.",
            "image_url": "https://public.runflow.io/images/models/_shared/base-engineer.png"
        },
        "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/black-forest-labs/flux-pro/kontext/runs \
  -H "Authorization: Bearer $RUNFLOW_API_KEY" \
  -H "Content-Type: application/json" \
  --data-binary @- <<'JSON'
{
    "input": {
        "prompt": "Add a fluffy orange tabby cat sleeping on the desk between the two monitors, curled up on a small cushion, one paw draped over the keyboard. The cat is illuminated by the monitor glow. Everything else stays exactly the same.",
        "image_url": "https://public.runflow.io/images/models/_shared/base-engineer.png"
    },
    "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                                                                                                           |
| ------------------ | ------- | -------- | ----------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------- |
| `prompt`           | string  | required | Any                                                               | Editing instruction describing the desired transformation.                                                            |
| `image_url`        | image   | required | Any                                                               | URL of the source image to edit.                                                                                      |
| `aspect_ratio`     | string  | optional | `21:9`, `16:9`, `4:3`, `3:2`, `1:1`, `2:3`, `3:4`, `9:16`, `9:21` | Output aspect ratio. Options: square\_hd, square, portrait\_4\_3, portrait\_16\_9, landscape\_4\_3, landscape\_16\_9. |
| `num_images`       | integer | optional | Any                                                               | Number of images to generate per request. Range: 1–4. Default: 1.                                                     |
| `guidance_scale`   | float   | optional | Any                                                               | How closely the model follows the prompt. Range: 1–20. Default: 3.5.                                                  |
| `output_format`    | string  | optional | `jpeg`, `png`                                                     | Output format. Options: "jpeg", "png". Default: "jpeg".                                                               |
| `safety_tolerance` | string  | optional | Any                                                               | Content moderation strictness. 1 = most strict, 6 = most permissive. Default: 2.                                      |
| `enhance_prompt`   | boolean | optional | Any                                                               | Automatically enhance the prompt for better results. Default: false.                                                  |
| `seed`             | integer | optional | Any                                                               | Random seed for reproducible outputs.                                                                                 |
| `sync_mode`        | boolean | optional | Any                                                               | Return media as data URI without storing in request history. Default: false.                                          |

## Output schema

| Field           | Type | Description                                                                                                                                                        |
| --------------- | ---- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| `outputs`       | json | Unified output array - one entry per generated artifact with url/type/width/height/duration/etc.                                                                   |
| `seed`          | json | Seed of the generated Image. It will be the same value of the one passed in the             input or the randomly generated that was used in case none was passed. |
| `model_data`    | json | Model-specific extra fields (prompt, description, actual\_prompt, masks, etc.) keyed by field name.                                                                |
| `nsfw_detected` | json | true if the provider flagged output as NSFW, false if cleared, null if not checked.                                                                                |
| `timing`        | json | Provider timing info (inference\_ms etc.), or null.                                                                                                                |

## 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/black-forest-labs/flux-pro/kontext)
* [API Reference](https://app.runflow.io/models/black-forest-labs/flux-pro/kontext?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>