# BFL Flux 2 Klein 4B Edit API

> Flux 2 Klein 4b by BFL - AI-powered image editing, style transfer, and transformation. Edit photos with natural language instructions, remove backgrounds, change styles, and enhance images effortlessly.

Source: https://www.sandbase.ai/model/bfl/flux-2/klein/4b/edit
API reference: https://www.sandbase.ai/model/bfl/flux-2/klein/4b/edit/docs

## Facts

- Provider: BFL
- Type: Image model
- Model ID: `bfl/flux-2/klein/4b/edit`
- Price: $0.02 per run
- Capabilities: image to image
- Billing: pay per use from one SandBase balance; no provider account or subscription needed

## Call it

- Unified Run API: `POST https://api.sandbase.ai/v1/run`

```bash
curl -X POST https://api.sandbase.ai/v1/run \
  -H "Authorization: Bearer $SANDBASE_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "model": "bfl/flux-2/klein/4b/edit",
  "images": [
    "https://static.sandbase.ai/examples/bfl/flux-2/klein/4b/edit/input_images_0.png"
  ],
  "prompt": "Turn this into a realistic image",
  "output_format": "png",
  "num_inference_steps": 4
}'
```

The response returns a run id; poll `GET https://api.sandbase.ai/v1/run/{id}` until the status is `completed` or `failed`.

## FAQ

### How do I call BFL Flux 2 Klein 4B Edit through SandBase?

Create a SandBase API key, then send requests with the model ID "bfl/flux-2/klein/4b/edit" to Unified Run API (/v1/run) at https://api.sandbase.ai. The request examples on this page show the exact payload.

### Do I need a separate BFL account?

No. One SandBase API key and balance gives you access to BFL Flux 2 Klein 4B Edit and the other models in the catalog; you do not need to sign up with BFL separately.

## README

### Flux 2 Klein 4B Edit

FLUX.2 [klein] 4B, the smallest FLUX.2 model, built for speed. Edit or combine images with an instruction.

#### Fields

| Field | Type | Default | Notes |
|---|---|---|---|
| `prompt` | string, required | — | Text instruction. |
| `images` | image URL[] | — | Images to edit or combine, Image 1, Image 2, … |
| `num_inference_steps` | integer 4–8 | 4 | More steps add detail and time. |
| `output_format` | `jpeg` / `png` | `png` | Output file format. |
| `aspect_ratio` | `21:9` / `16:9` / `3:2` / `4:3` / `5:4` / `1:1` / `4:5` / `3:4` / `2:3` / `9:16` | — | Output shape. |
| `seed` | integer | random | Fix it to compare prompt changes. |

#### Billing

$0.02 per image.

| Request | Price |
|---|---|
| One image | $0.02 |

Failed runs are not charged.

#### Prompting

- Say which image is the base and what each other image contributes.
- List what must not change.

#### Limits

- One output image per request.

#### Also on SandBase

Other FLUX.2 endpoints: `bfl/flux-2/max/edit`, `bfl/flux-2/pro/edit`, `bfl/flux-2/flex/edit`, `bfl/flux-2/dev/edit`, `bfl/flux-2/klein/4b`.