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

# FLUX 3 Image Klein Base

> The undistilled FLUX 3 Image Klein checkpoint from Black Forest Labs: 50-step sampling, CFG guidance and negative prompt. See parameters, pricing, response fields, and API examples.

Generate and edit images with FLUX 3 Image Klein Base, the undistilled 5.6B open-weight FLUX 3 checkpoint. It samples at 50 steps by default and adds classifier-free guidance and a negative prompt on top of the same text-to-image, editing and multi-reference route as the distilled model.

More on this model: [FLUX 3 Image Klein Base API page](https://unifically.com/models/flux-3-image-klein-base).

## Model

```
black-forest-labs/flux-3-image-klein-base
```

## Parameters

| Parameter | Type | Required | Default | Description |
| - | - | - | - | - |
| `prompt` | string | Yes | - | Text description of the image, or the edit to apply to the reference images |
| `negative_prompt` | string | No | `null` | What to keep out of the image. Ignored when `guidance` is `1` or lower |
| `aspect_ratio` | string | No | `"16:9"` | `"21:9"`, `"16:9"`, `"4:3"`, `"1:1"`, `"3:4"`, `"9:16"`, `"9:21"` |
| `resolution` | string | No | `"1mp"` | `"0.6mp"`, `"1mp"`, `"2mp"`, `"4mp"` |
| `image_urls` | string\[] | No | `null` | Up to 4 reference image URLs for editing or multi-reference generation |
| `steps` | integer | No | `50` | Sampling steps, `1`-`50` |
| `guidance` | float | No | `3.5` | CFG guidance scale, `1`-`20` |
| `seed` | integer | No | random | Seed for reproducibility |
| `nsfw_check` | boolean | No | `true` | Check uploaded media inputs for NSFW content |

<Note>The distilled [FLUX 3 Image Klein](/models/image/flux/flux-3-image-klein) runs about three times faster at the same size and is the default for production volume. Use Base for guidance experiments and to match LoRAs trained on the Base weights.</Note>

## Example Request

```bash theme={null}
curl -X POST https://api.unifically.com/v1/tasks   -H "Content-Type: application/json"   -H "Authorization: Bearer YOUR_API_KEY"   -d '{
    "model": "black-forest-labs/flux-3-image-klein-base",
    "input": {
      "prompt": "Studio product shot of a matte black ceramic pour-over coffee dripper on a walnut slab",
      "negative_prompt": "text, watermark, extra objects",
      "aspect_ratio": "16:9",
      "resolution": "1mp",
      "guidance": 3.5
    }
  }'
```

## Response

```json theme={null}
{
  "code": 200,
  "success": true,
  "data": {
    "task_id": "abc123def456",
    "status": "processing"
  }
}
```

<Note>
  **Volume discounts** are available for almost all models. Reach out at [contact@unifically.com](mailto:contact@unifically.com) to discuss custom pricing.
</Note>


This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.