# FLUX.2 [klein] 4B LoRA · Edit API

> Editing klein 4B singkat dengan LoRA, dibatasi 4 hingga 8 langkah inferensi

Mengedit gambar dengan model klein 4B terdistilasi dari prompt dan hingga 4 gambar dalam `image_urls`, dengan hingga 3 LoRA dalam `loras`. `num_inference_steps` berbawaan 4 dan dibatasi hingga 8. Ukuran output berbawaan ukuran input kecuali `image_size` diatur. Hingga 4 hasil sebagai jpeg, png, atau webp.

- Model id: `flux-2/klein/4b/edit/lora`
- Made by: Black Forest Labs
- Category: Image Editing
- Output: image
- Price per megapixel: $0.01 / megapixel (cheapest run $0.01 (10 API credits))
- Run: `POST https://api.doitong.com/v1/run/flux-2/klein/4b/edit/lora`
- Quote: `POST https://api.doitong.com/v1/quote/flux-2/klein/4b/edit/lora`
- Docs page: https://doitong.com/id/developers/models/flux-2/klein/4b/edit/lora

## Pricing

Price: **$0.01 / megapixel**. Price per megapixel: the input files are measured before the run (length, resolution, frame rate). The quote measures the same files and is exactly what the run charges.

The full example input below costs $0.02 = 20 API credits (2 MP × $0.01).

Prices are the upstream price in USD, paid from the API balance in API credits (1000 API credits = 1 USD). `POST https://api.doitong.com/v1/quote/flux-2/klein/4b/edit/lora` with the same JSON body returns the exact price for that input; the quote is exactly what a run charges. Invalid input is never charged and failed or canceled requests are refunded automatically.

## Input parameters

Send either the canonical name or the native field name (not both). Canonical names are the same across models.

| Parameter | Canonical name | Type | Required | Default | Allowed values / range | Description |
|---|---|---|---|---|---|---|
| `prompt` |  | string | yes |  |  | Prompt yang menjelaskan pengeditan gambar. |
| `seed` |  | integer \| null | no |  |  | Penggantian seed pembuatan; jika tidak disertakan, pembuatan memilih seed secara acak. |
| `num_inference_steps` |  | integer | no | `4` | 4 – 8 | Jumlah langkah inferensi yang dijalankan. |
| `image_size` |  | object {width, height} \| enum (string) \| null | no |  | `square_hd`, `square`, `portrait_4_3`, `portrait_16_9`, `landscape_4_3`, `landscape_16_9` | Dimensi gambar output; jika dihilangkan, dimensinya sama dengan gambar input. |
| `num_images` | `num_outputs` | integer | no | `1` | 1 – 4 | Jumlah gambar yang diminta untuk dibuat. |
| `enable_safety_checker` |  | boolean | no | `true` |  | Pemeriksaan keamanan, yang mengembalikan gambar hitam sebagai pengganti gambar yang ditandai tidak aman. Nilai true mengaktifkan pemeriksaan; false menonaktifkannya hanya untuk akun yang berwenang, sedangkan permintaan tanpa otorisasi tetap diperiksa. |
| `output_format` |  | enum (string) | no | `png` | `jpeg`, `png`, `webp` | Format file untuk gambar hasil. |
| `image_urls` | `images` | array of image URL | yes |  |  | URL gambar yang akan diedit, dibatasi hingga 4 gambar. |
| `loras` |  | array of object {path, scale} | no | `[]` |  | Bobot LoRA yang akan diterapkan, dibatasi hingga 3 entri. |
| `loras[].path` |  | string | yes |  |  | Lokasi bobot LoRA, ditentukan sebagai URL, ID repositori HuggingFace dalam format owner/repo, atau path lokal. |
| `loras[].scale` |  | number | no | `1` | 0 – 4 | Faktor penskalaan yang diterapkan pada LoRA, dengan rentang 0.0 hingga 4.0. |

File parameters (`images`) take a public `https://` URL, a `data:` URI up to 10 MB, or the `file_url` of an upload from `POST /files`.

## Example input

Required parameters only:

```json
{
  "prompt": "A red fox trots through fresh snow at sunrise, soft golden light, shallow depth of field",
  "images": [
    "https://content.doitong.com/images/showcase/v3/gen_fox_cartoon.jpg"
  ]
}
```

A fuller example:

```json
{
  "prompt": "A red fox trots through fresh snow at sunrise, soft golden light, shallow depth of field",
  "image_urls": [
    "https://content.doitong.com/images/showcase/v3/gen_fox_cartoon.jpg"
  ]
}
```

## Run it

Set `DOITONG_API_KEY` to a key from https://doitong.com/developers/dashboard#keys. `?wait=20` returns the finished request in the same call when it is ready within 20 seconds; otherwise poll `GET /requests/{id}` (it also accepts `?wait=`), or pass `webhook_url`.

### curl

```bash
# Run the model; wait up to 20 s for the finished result in the same call
curl -X POST "https://api.doitong.com/v1/run/flux-2/klein/4b/edit/lora?wait=20" \
  -H "Authorization: Bearer $DOITONG_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "prompt": "A red fox trots through fresh snow at sunrise, soft golden light, shallow depth of field",
    "image_urls": [
      "https://content.doitong.com/images/showcase/v3/gen_fox_cartoon.jpg"
    ]
  }'

# Still "queued" or "running"? Poll with the id from the response:
curl "https://api.doitong.com/v1/requests/REQUEST_ID?wait=20" \
  -H "Authorization: Bearer $DOITONG_API_KEY"
```

### JavaScript

```javascript
const API = "https://api.doitong.com/v1";
const headers = {
  "Authorization": "Bearer " + process.env.DOITONG_API_KEY,
  "Content-Type": "application/json",
};

// Run the model; wait up to 20 s for the finished result in the same call
let res = await fetch(API + "/run/flux-2/klein/4b/edit/lora?wait=20", {
  method: "POST",
  headers,
  body: JSON.stringify({
    "prompt": "A red fox trots through fresh snow at sunrise, soft golden light, shallow depth of field",
    "image_urls": [
      "https://content.doitong.com/images/showcase/v3/gen_fox_cartoon.jpg"
    ]
  }),
});
let request = await res.json();
if (!res.ok) throw new Error(request.error.code + ": " + request.error.message);

// Not finished yet: long-poll until it is
while (request.status === "queued" || request.status === "running") {
  res = await fetch(API + "/requests/" + request.id + "?wait=20", { headers });
  request = await res.json();
}
if (request.status !== "succeeded") throw new Error(JSON.stringify(request.error));
console.log(request.outputs.map((o) => o.url), request.cost.credits + " API credits ($" + request.cost.usd + ")");
```

### Python

```python
import os
import requests

API = "https://api.doitong.com/v1"
headers = {"Authorization": "Bearer " + os.environ["DOITONG_API_KEY"]}

payload = {
    "prompt": "A red fox trots through fresh snow at sunrise, soft golden light, shallow depth of field",
    "image_urls": [
        "https://content.doitong.com/images/showcase/v3/gen_fox_cartoon.jpg",
    ],
}

# Run the model; wait up to 20 s for the finished result in the same call
r = requests.post(API + "/run/flux-2/klein/4b/edit/lora", params={"wait": 20}, json=payload, headers=headers)
request = r.json()
if not r.ok:
    raise RuntimeError(request["error"]["code"] + ": " + request["error"]["message"])

# Not finished yet: long-poll until it is
while request["status"] in ("queued", "running"):
    request = requests.get(API + "/requests/" + request["id"], params={"wait": 20}, headers=headers).json()
if request["status"] != "succeeded":
    raise RuntimeError(request["error"])
print([o["url"] for o in request["outputs"]], request["cost"]["credits"], "API credits", "$" + request["cost"]["usd"])
```

### MCP

The MCP server at `https://api.doitong.com/v1/mcp` exposes the tools `search_models`, `get_model`, `quote`, `run`, `get_request`, `cancel_request`, `list_requests`, `create_upload` and `get_account`. A `run` call for this model:

```json
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "run",
    "arguments": {
      "model_id": "flux-2/klein/4b/edit/lora",
      "input": {
        "prompt": "A red fox trots through fresh snow at sunrise, soft golden light, shallow depth of field",
        "image_urls": [
          "https://content.doitong.com/images/showcase/v3/gen_fox_cartoon.jpg"
        ]
      },
      "wait_seconds": 20
    }
  }
}
```

## Response

Every call returns a request object. `status` is one of `queued`, `running`, `succeeded`, `failed`, `canceled`. `outputs` lists the generated files with URLs on our storage (kept forever, or 7 days with `?storage=temporary`; `storage` says which); `output` is the model's own result object with the same URLs.

```json
{
  "id": "req_8k2m4q7x1z9c3v5b6n0p2r4t",
  "object": "request",
  "model": "flux-2/klein/4b/edit/lora",
  "status": "succeeded",
  "created_at": "2026-10-20T12:00:00Z",
  "started_at": "2026-10-20T12:00:02Z",
  "completed_at": "2026-10-20T12:00:09Z",
  "queue_position": null,
  "cost": {
    "credits": 20,
    "usd": "0.02",
    "charged": 20,
    "refunded": 0
  },
  "input": {
    "prompt": "A red fox trots through fresh snow at sunrise, soft golden light, shallow depth of field",
    "image_urls": [
      "https://content.doitong.com/images/showcase/v3/gen_fox_cartoon.jpg"
    ]
  },
  "output": {
    "images": [
      {
        "url": "https://content.doitong.com/dev-api/2026/10/20/req_8k2m4q7x1z9c3v5b6n0p2r4t/0-output.jpeg",
        "content_type": "image/jpeg",
        "file_name": "0-output.jpeg",
        "file_size": 1843200,
        "width": 1024,
        "height": 768
      }
    ],
    "timings": {},
    "seed": 42,
    "has_nsfw_concepts": [
      false
    ],
    "prompt": "string"
  },
  "outputs": [
    {
      "type": "image",
      "url": "https://content.doitong.com/dev-api/2026/10/20/req_8k2m4q7x1z9c3v5b6n0p2r4t/0-output.jpeg",
      "content_type": "image/jpeg",
      "file_size": 1843200,
      "width": 1024,
      "height": 768,
      "stored": true
    }
  ],
  "error": null,
  "metrics": {
    "inference_seconds": 6.8
  },
  "urls": {
    "self": "https://api.doitong.com/v1/requests/req_8k2m4q7x1z9c3v5b6n0p2r4t",
    "cancel": "https://api.doitong.com/v1/requests/req_8k2m4q7x1z9c3v5b6n0p2r4t/cancel"
  }
}
```

### Output fields (`output`)

| Field | Type | Description |
|---|---|---|
| `images` | array of object {url, content_type, file_name, file_size, width, height} | Gambar hasil pengeditan. |
| `timings` | object |  |
| `seed` | integer | Seed pembuatan gambar, termasuk nilai yang dipilih secara acak jika input tidak menyertakan seed; jika tidak, nilai yang diberikan akan diulang. |
| `has_nsfw_concepts` | array of boolean | Menunjukkan apakah konsep NSFW muncul dalam gambar yang dihasilkan. |
| `prompt` | string | Prompt yang digunakan selama pembuatan gambar. |

## Related models

- [FLUX.2 \[klein\] 4B Base LoRA](https://doitong.com/developers/models/flux-2/klein/4b/base/lora.md) (`flux-2/klein/4b/base/lora`): $0.016 / megapixel
- [FLUX.2 \[klein\] 4B LoRA](https://doitong.com/developers/models/flux-2/klein/4b/lora.md) (`flux-2/klein/4b/lora`): $0.01 / megapixel
- [FLUX.2 \[klein\] 9B Base LoRA](https://doitong.com/developers/models/flux-2/klein/9b/base/lora.md) (`flux-2/klein/9b/base/lora`): $0.02 / megapixel
- [FLUX.2 \[klein\] 9B LoRA](https://doitong.com/developers/models/flux-2/klein/9b/lora.md) (`flux-2/klein/9b/lora`): $0.015 / megapixel
- [FLUX.2 \[klein\] 4B Base LoRA · Edit](https://doitong.com/developers/models/flux-2/klein/4b/base/edit/lora.md) (`flux-2/klein/4b/base/edit/lora`): $0.016 / megapixel
- [FLUX.2 \[klein\] 9B Base LoRA · Edit](https://doitong.com/developers/models/flux-2/klein/9b/base/edit/lora.md) (`flux-2/klein/9b/base/edit/lora`): $0.02 / megapixel
- [FLUX.2 \[klein\] 9B LoRA · Edit](https://doitong.com/developers/models/flux-2/klein/9b/edit/lora.md) (`flux-2/klein/9b/edit/lora`): $0.015 / megapixel
- [FLUX.1 Kontext \[pro\]](https://doitong.com/developers/models/flux-pro/kontext.md) (`flux-pro/kontext`): $0.04 / image

## Links

- HTML page: https://doitong.com/developers/models/flux-2/klein/4b/edit/lora
- All models and guides for AI agents: https://doitong.com/developers/llms.txt
- OpenAPI 3.1 with this model's typed request body: https://doitong.com/developers/openapi.json?model=flux-2/klein/4b/edit/lora
- Errors: https://doitong.com/developers/docs/errors
- Model details as JSON: https://api.doitong.com/v1/models/flux-2/klein/4b/edit/lora