# FLUX.3 Klein API

> He tuhinga-ki-te-atahanga me ngā rahi 4K taketake, te whakahaere tahora pouaka here kōwhiringa me ngā atahanga tae atu ki te 4 mō ia tono

Ka whakaputa atahanga mai i tētahi `prompt` kuputuhi whai taipitopito. Ka taea ia taha o `image_size` mai i te 256 ki te 4096 pika, ā, ka taea te tono kia 1 ki te 4 atahanga mō ia karanga. Mā te 32 `bounding_boxes` rawa e āhei ai te whakanoho i ngā ahanoa kua whakaingoatia ki ngā tūnga kua tautuhia i te anga. Ko te putanga he png, jpeg, webp rānei, ā, ka taea te whakakā, te whakaweto rānei i te whakawhānui tohutohu.

- Model id: `blackforestlabs/flux-3/klein/text-to-image`
- Made by: Black Forest Labs
- Category: Text to Image
- Output: image
- Price per run: from $0.008 / run of output image (cheapest run $0.008 (8 API credits))
- Run: `POST https://api.doitong.ru/v1/run/blackforestlabs/flux-3/klein/text-to-image`
- Quote: `POST https://api.doitong.ru/v1/quote/blackforestlabs/flux-3/klein/text-to-image`
- Docs page: https://doitong.com/mi/developers/models/blackforestlabs/flux-3/klein/text-to-image

## Pricing

Price: **from $0.008 / run of output image** (the lowest tier; the quote prices your exact input). Price per run: 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 $0.009 = 9 API credits (1 run × $0.009).

Prices are the upstream price in USD, paid from the API balance in API credits (1000 API credits = 1 USD). `POST https://api.doitong.ru/v1/quote/blackforestlabs/flux-3/klein/text-to-image` 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 |  |  | Tohutohu whakaputa atahanga e whakaahua taipitopito ana i te kaupapa, te anga, te rama me te papamuri, e rite ana ki ngā tapanga taipitopito i whakamahia hei whakangungu i te tauira. |
| `enable_prompt_expansion` |  | boolean | no | `true` |  | Whakawhānui tohutohu hei tapanga taipitopito i mua i te whakaputanga, ka whakahohea ina true. Mō te whakatika, ka ū te tapanga ki ngā atahanga tohutoro. |
| `seed` |  | integer \| null | no |  |  | Kākano mō ngā atahanga ka taea te whakahoki anō: mā te tohutohu me te kākano ōrite ka puta he atahanga ōrite ina kāore te putanga tauira i whakarerekēhia. |
| `num_images` | `num_outputs` | integer | no | `1` | 1 – 4 | Te tatau atahanga e tonoa ana mō te whakaputanga. |
| `enable_safety_checker` |  | boolean | no | `true` |  | Whakahohe kaitaki haumaru; mā true e whakahohe te tirotiro. |
| `output_format` |  | enum (string) | no | `png` | `jpeg`, `png`, `webp` | Te hōputu kōnae mō te atahanga ka puta. |
| `image_size` |  | object {width, height} \| enum (string) | no | `square_hd` | `square_hd`, `square`, `portrait_4_3`, `portrait_16_9`, `landscape_4_3`, `landscape_16_9` | Tautuhia motuhake te whānui me te teitei putanga ki waenga i te 256–4096 pika, me te tautoko i te whakaputa 4K taketake. |
| `bounding_boxes` |  | array of object {label, description, box} \| null | no |  | ≤ 32 items | Tahora pouaka kōwhiringa e here ana i ia ahanoa kua whakaahuatia ki tōna pouaka; tautuhia ngā pouaka mā ngā tapanga tohutohu, hei tauira `A red fox <fox> sits under a red umbrella <umbrella>`. Ka whakaatu ngā taunga i ngā tapa pouaka hei hautanga o ngā rahinga atahanga, ka inehia mai i te pūtake kokonga mauī-runga (0, 0). |
| `bounding_boxes[].label` |  | string \| null | no |  | ≤ 64 characters | Tapanga poto mō te pouaka, pērā i `fox`; ko `obj_<n>` te taunoa. Whakaurua `<fox>` ki te tohutohu hei hono i ōna kupu ki te pouaka; ka tāpirihia ngā pouaka kāore i whakahuatia ki te horopaki. |
| `bounding_boxes[].description` |  | string | yes |  | ≤ 500 characters | Ahanoa hei whakaputa i roto i te pouaka, tae atu ki tōna āhua. |
| `bounding_boxes[].box` |  | object {x_min, y_min, x_max, y_max} | yes |  |  | Tūnga ahanoa i roto i te atahanga putanga. |
| `bounding_boxes[].box.x_min` |  | number | yes |  | 0 – 1 | Rāhenga mauī e whakaatuhia ana ki te whānui atahanga, mai i te 0 ki te 1. |
| `bounding_boxes[].box.y_min` |  | number | yes |  | 0 – 1 | Rāhenga runga e whakaatuhia ana ki te teitei atahanga, mai i te 0 ki te 1. |
| `bounding_boxes[].box.x_max` |  | number | yes |  | 0 – 1 | Rāhenga matau e whakaatuhia ana ki te whānui atahanga, mai i te 0 ki te 1. |
| `bounding_boxes[].box.y_max` |  | number | yes |  | 0 – 1 | Rāhenga raro e whakaatuhia ana ki te teitei atahanga, mai i te 0 ki te 1. |

## Example input

Required parameters only:

```json
{
  "prompt": "A red fox trots through fresh snow at sunrise, soft golden light, shallow depth of field"
}
```

A fuller example:

```json
{
  "prompt": "A red fox trots through fresh snow at sunrise, soft golden light, shallow depth of field"
}
```

## 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.ru/v1/run/blackforestlabs/flux-3/klein/text-to-image?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"
  }'

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

### JavaScript

```javascript
const API = "https://api.doitong.ru/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/blackforestlabs/flux-3/klein/text-to-image?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"
  }),
});
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.ru/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",
}

# Run the model; wait up to 20 s for the finished result in the same call
r = requests.post(API + "/run/blackforestlabs/flux-3/klein/text-to-image", 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.ru/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": "blackforestlabs/flux-3/klein/text-to-image",
      "input": {
        "prompt": "A red fox trots through fresh snow at sunrise, soft golden light, shallow depth of field"
      },
      "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": "blackforestlabs/flux-3/klein/text-to-image",
  "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": 9,
    "usd": "0.009",
    "charged": 9,
    "refunded": 0
  },
  "input": {
    "prompt": "A red fox trots through fresh snow at sunrise, soft golden light, shallow depth of field"
  },
  "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.ru/v1/requests/req_8k2m4q7x1z9c3v5b6n0p2r4t",
    "cancel": "https://api.doitong.ru/v1/requests/req_8k2m4q7x1z9c3v5b6n0p2r4t/cancel"
  }
}
```

### Output fields (`output`)

| Field | Type | Description |
|---|---|---|
| `images` | array of object {url, content_type, file_name, file_size, width, height} | Ngā atahanga i whakaputaina e te tauira. |
| `timings` | object | Ngā pārongo wā mō te tukanga whakaputa. |
| `seed` | integer | Kākano whakaputa mō te atahanga tuatahi. |
| `has_nsfw_concepts` | array of boolean | Ka tohu mēnā ka puta ngā ariā NSFW i ngā atahanga kua whakaputaina. |
| `prompt` | string | Te tohutohu e whakamahia ana i te whakaputanga atahanga. |

## Related models

- [FLUX.3 Klein Image Editing](https://doitong.com/developers/models/blackforestlabs/flux-3/klein/edit-image.md) (`blackforestlabs/flux-3/klein/edit-image`): from $0.008 / run of output image
- [FLUX.1 \[dev\]](https://doitong.com/developers/models/flux/dev.md) (`flux/dev`): $0.025 / megapixel
- [FLUX.1 \[schnell\]](https://doitong.com/developers/models/flux/schnell.md) (`flux/schnell`): $0.003 / megapixel
- [FLUX.2 \[dev\]](https://doitong.com/developers/models/flux-2.md) (`flux-2`): $0.012 / megapixel
- [FLUX.2 \[pro\]](https://doitong.com/developers/models/flux-2-pro.md) (`flux-2-pro`): $0.015 / megapixel of output image
- [GPT Image 2.5 Text to Image](https://doitong.com/developers/models/openai/gpt-image-2.5/flare/text-to-image.md) (`openai/gpt-image-2.5/flare/text-to-image`): from $0.008 / image
- [Ideogram V4.5](https://doitong.com/developers/models/ideogram/v4.5.md) (`ideogram/v4.5`): from $0.03 / image
- [Nano Banana 2](https://doitong.com/developers/models/nano-banana-2.md) (`nano-banana-2`): from $0.06 / image

## Links

- HTML page: https://doitong.com/developers/models/blackforestlabs/flux-3/klein/text-to-image
- 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=blackforestlabs/flux-3/klein/text-to-image
- Errors: https://doitong.com/developers/docs/errors
- Model details as JSON: https://api.doitong.ru/v1/models/blackforestlabs/flux-3/klein/text-to-image