# FLUX.3 Klein API

> Testun-i-ddelwedd gyda meintiau 4K brodorol, rheolaeth cynllun blychau terfyn dewisol a hyd at 4 delwedd fesul cais

Yn cynhyrchu delweddau o `prompt` testun manwl. Gall pob ochr o `image_size` amrywio o 256 i 4096 picsel, a gallwch ofyn am 1 i 4 delwedd fesul galwad. Mae hyd at 32 `bounding_boxes` yn caniatáu gosod gwrthrychau a enwir mewn safleoedd penodol yn y ffrâm. Gall yr allbwn fod yn png, jpeg neu webp, a gellir troi ehangu anogiad ymlaen neu i ffwrdd.

- 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/cy/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 |  |  | Cyfarwyddiadau cynhyrchu delwedd sy'n disgrifio'r pwnc, y fframio, y goleuo a'r cefndir yn fanwl, gan gyfateb i'r capsiynau manwl a ddefnyddiwyd i hyfforddi'r model. |
| `enable_prompt_expansion` |  | boolean | no | `true` |  | Ehangu'r anogiad yn gapsiwn manwl cyn cynhyrchu, wedi'i alluogi pan fo true. Ar gyfer golygu, mae'r capsiwn yn seiliedig ar y delweddau cyfeirnod. |
| `seed` |  | integer \| null | no |  |  | Hadau ar gyfer delweddau atgynhyrchadwy: mae anogiad a hadau unfath yn cynhyrchu delwedd unfath pan nad yw fersiwn y model wedi newid. |
| `num_images` | `num_outputs` | integer | no | `1` | 1 – 4 | Cyfrif delweddau y gofynnir amdano ar gyfer cynhyrchu. |
| `enable_safety_checker` |  | boolean | no | `true` |  | Ysgogi gwiriwr diogelwch; mae true yn galluogi'r gwiriad. |
| `output_format` |  | enum (string) | no | `png` | `jpeg`, `png`, `webp` | Fformat ffeil y ddelwedd sy'n deillio. |
| `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` | Gosodwch led ac uchder yr allbwn yn annibynnol o fewn 256–4096 picsel, gan gefnogi cynhyrchu 4K brodorol. |
| `bounding_boxes` |  | array of object {label, description, box} \| null | no |  | ≤ 32 items | Cynllun blwch dewisol sy'n cyfyngu pob gwrthrych a ddisgrifir i'w flwch penodedig; nodwch flychau drwy labeli anogiad, e.e. `A red fox <fox> sits under a red umbrella <umbrella>`. Mae cyfesurynnau'n mynegi ymylon blychau fel ffracsiynau o ddimensiynau'r ddelwedd, wedi'u mesur o'r tarddbwynt chwith uchaf (0, 0). |
| `bounding_boxes[].label` |  | string \| null | no |  | ≤ 64 characters | Label gwrthrych byr ar gyfer y blwch, megis `fox`; y rhagosodedig yw `obj_<n>`. Cynhwyswch `<fox>` yn yr anogiad i gysylltu ei eiriau â'r blwch; ychwanegir blychau na chrybwyllir yn yr anogiad at yr olygfa. |
| `bounding_boxes[].description` |  | string | yes |  | ≤ 500 characters | Gwrthrych i'w rendro o fewn y blwch, gan gynnwys ei olwg. |
| `bounding_boxes[].box` |  | object {x_min, y_min, x_max, y_max} | yes |  |  | Lleoliad gwrthrych o fewn y ddelwedd allbwn. |
| `bounding_boxes[].box.x_min` |  | number | yes |  | 0 – 1 | Ffin chwith wedi'i mynegi mewn perthynas â lled y ddelwedd, o 0 i 1. |
| `bounding_boxes[].box.y_min` |  | number | yes |  | 0 – 1 | Ffin uchaf wedi'i mynegi mewn perthynas ag uchder y ddelwedd, o 0 i 1. |
| `bounding_boxes[].box.x_max` |  | number | yes |  | 0 – 1 | Ffin dde wedi'i mynegi mewn perthynas â lled y ddelwedd, o 0 i 1. |
| `bounding_boxes[].box.y_max` |  | number | yes |  | 0 – 1 | Ffin isaf wedi'i mynegi mewn perthynas ag uchder y ddelwedd, o 0 i 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} | Delweddau a gynhyrchir gan y model. |
| `timings` | object | Gwybodaeth amseru ar gyfer y broses gynhyrchu. |
| `seed` | integer | Hadau cynhyrchu ar gyfer y ddelwedd gyntaf. |
| `has_nsfw_concepts` | array of boolean | Yn nodi a yw cysyniadau NSFW yn ymddangos yn y delweddau a gynhyrchir. |
| `prompt` | string | Anogiad a ddefnyddir wrth gynhyrchu delweddau. |

## 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