# FLUX.3 Klein API

> Teacsa-gu-ìomhaigh le meudan dùthchasach 4K, smachd cruth bogsaichean crìche roghainneil agus suas ri 4 ìomhaighean gach iarrtas

Gin ìomhaighean à `prompt` teacsa mionaideach. Faodaidh gach taobh de `image_size` a bhith eadar 256 agus 4096 piogsail, agus faodaidh tu 1 gu 4 ìomhaighean iarraidh gach gairm. Leigidh suas ri 32 `bounding_boxes` leat nithean ainmichte a chur aig suidheachaidhean sònraichte san fhrèam. Faodaidh an toradh a bhith png, jpeg no webp, agus faodar leudachadh prompt a thogail no a dhùnadh.

- 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/gd/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 |  |  | Stiùiridhean gineadh ìomhaigh a’ mìneachadh a’ chuspair, frèamadh, solais agus cùl-raoin gu mionaideach, a’ maidseadh nan captionan mionaideach a chaidh a chleachdadh airson am modail a thrèanadh. |
| `enable_prompt_expansion` |  | boolean | no | `true` |  | Leudachadh prompt gu caption mhionaideach ro ghineadh, air a chomasachadh nuair a tha e fìor. Airson deasachaidh, tha an caption stèidhichte air na h-ìomhaighean iomraidh. |
| `seed` |  | integer \| null | no |  |  | Sìol airson ìomhaighean ath-riochdachail: cruthaichidh prompt agus sìol co-ionann an aon ìomhaigh nuair nach eil tionndadh a’ mhodail air atharrachadh. |
| `num_images` | `num_outputs` | integer | no | `1` | 1 – 4 | Àireamh nan ìomhaighean a chaidh iarraidh airson gineadh. |
| `enable_safety_checker` |  | boolean | no | `true` |  | Gnìomhachadh an t-sgrùdaiche sàbhailteachd; tha true a’ comasachadh sgrùdaidh. |
| `output_format` |  | enum (string) | no | `png` | `jpeg`, `png`, `webp` | Cruth faidhle na h-ìomhaigh a thig às. |
| `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` | Suidhich leud is àirde an às-chuir gu neo-eisimeileach taobh a-staigh 256–4096 piogsail, le taic do ghineadh dùthchasach 4K. |
| `bounding_boxes` |  | array of object {label, description, box} \| null | no |  | ≤ 32 items | Cruth bogsa roghainneil a chuireas gach nì a chaidh a mhìneachadh taobh a-staigh a’ bhogsa ainmichte aige; comharraich bogsaichean tro bhileagan a’ phrompt, m.e. `A red fox <fox> sits under a red umbrella <umbrella>`. Tha na co-chomharran a’ cur oirean a’ bhogsa an cèill mar bloighean de mheudan na h-ìomhaigh, air an tomhas bhon tùs gu h-àrd air an taobh chlì (0, 0). |
| `bounding_boxes[].label` |  | string \| null | no |  | ≤ 64 characters | Bileag ghoirid nì airson a’ bhogsa, leithid `fox`; is e `obj_<n>` am bun-roghainn. Cuir `<fox>` sa phrompt gus na faclan aige a cheangal ris a’ bhogsa; thèid bogsaichean nach eil air an ainmeachadh sa phrompt a chur ris an t-sealladh. |
| `bounding_boxes[].description` |  | string | yes |  | ≤ 500 characters | Nì ri renderadh taobh a-staigh a’ bhogsa, a’ gabhail a-steach a choltas. |
| `bounding_boxes[].box` |  | object {x_min, y_min, x_max, y_max} | yes |  |  | Suidheachadh an nì taobh a-staigh na h-ìomhaigh às-chuir. |
| `bounding_boxes[].box.x_min` |  | number | yes |  | 0 – 1 | Crìoch chlì air a cur an cèill an coimeas ri leud na h-ìomhaigh, bho 0 gu 1. |
| `bounding_boxes[].box.y_min` |  | number | yes |  | 0 – 1 | Crìoch àrd air a cur an cèill an coimeas ri àirde na h-ìomhaigh, bho 0 gu 1. |
| `bounding_boxes[].box.x_max` |  | number | yes |  | 0 – 1 | Crìoch dheas air a cur an cèill an coimeas ri leud na h-ìomhaigh, bho 0 gu 1. |
| `bounding_boxes[].box.y_max` |  | number | yes |  | 0 – 1 | Crìoch ìosal air a cur an cèill an coimeas ri àirde na h-ìomhaigh, bho 0 gu 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} | Ìomhaighean a chaidh a chruthachadh leis a’ mhodail. |
| `timings` | object | Fiosrachadh tìm mun phròiseas gineadh. |
| `seed` | integer | Sìol gineadh airson a’ chiad ìomhaigh. |
| `has_nsfw_concepts` | array of boolean | A’ comharrachadh a bheil bun-bheachdan NSFW a’ nochdadh anns na h-ìomhaighean a chaidh a ghineadh. |
| `prompt` | string | Prompt a chaidh a chleachdadh rè gineadh ìomhaighe. |

## 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