# FLUX.1 [dev] API

> Le modèle FLUX polyvalent à poids ouverts, plus net et plus fidèle aux longues invites que schnell.

Modèle FLUX de 12 milliards de paramètres distillé avec guidage, doté d’un programme complet d’échantillonnage (28 étapes par défaut, rég­lables de 1 à 50) et d’une échelle de guidage ajustable. Il suit les invites détaillées et génère les mains, les visages et les textes courts nettement mieux que la variante schnell, à un prix plus élevé. Tailles prédéfinies ou personnalisées, jusqu’à quatre images par requête, sortie JPEG ou PNG.

- Model id: `flux/dev`
- Made by: Black Forest Labs
- Category: Text to Image
- Output: image
- Price: $0.025 / megapixel (cheapest run $0.025 (25 API credits))
- Run: `POST https://api.doitong.com/v1/run/flux/dev`
- Quote: `POST https://api.doitong.com/v1/quote/flux/dev`
- Docs page: https://doitong.com/fr-CA/developers/models/flux/dev

## Pricing

Price: **$0.025 / megapixel**. Billed per megapixel of output (width × height of every image). Each image is rounded up to a whole megapixel.

The full example input below costs $0.025 = 25 API credits (1 MP × 25 API credits).

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/dev` 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 |  |  | Invite qui guide la génération d’image. |
| `image_size` |  | object {width, height} \| enum (string) | no | `landscape_4_3` | `square_hd`, `square`, `portrait_4_3`, `portrait_16_9`, `landscape_4_3`, `landscape_16_9` | Dimensions de l’image générée. |
| `num_inference_steps` |  | integer | no | `28` | 1 – 50 | Nombre d’étapes d’inférence à exécuter. |
| `seed` |  | integer \| null | no |  |  | Valeur de départ pour des images reproductibles : une invite et une valeur de départ identiques produisent une image identique lorsque la version du modèle est inchangée. |
| `guidance_scale` |  | number | no | `3.5` | 1 – 20 | Intensité d’adhésion à l’invite pour la sélection d’images, exprimée comme CFG (Classifier Free Guidance). |
| `num_images` | `num_outputs` | integer | no | `1` | 1 – 4 | Nombre d’images demandé pour la génération. |
| `output_format` |  | enum (string) | no | `jpeg` | `jpeg`, `png` | Format de fichier de l’image obtenue. |
| `acceleration` |  | enum (string) | no | `none` | `none`, `regular`, `high` | Accélération de la génération; des réglages plus élevés réduisent le temps nécessaire pour générer les résultats. |

## Example input

Required parameters only:

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

A fuller example:

```json
{
  "prompt": "A red fox trots through fresh snow at sunrise, soft golden light, shallow depth of field, telephoto lens",
  "image_size": "landscape_4_3",
  "num_outputs": 1
}
```

## 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/dev?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, telephoto lens",
    "image_size": "landscape_4_3",
    "num_outputs": 1
  }'

# 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/dev?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, telephoto lens",
    "image_size": "landscape_4_3",
    "num_outputs": 1
  }),
});
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, telephoto lens",
    "image_size": "landscape_4_3",
    "num_outputs": 1,
}

# Run the model; wait up to 20 s for the finished result in the same call
r = requests.post(API + "/run/flux/dev", 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/dev",
      "input": {
        "prompt": "A red fox trots through fresh snow at sunrise, soft golden light, shallow depth of field, telephoto lens",
        "image_size": "landscape_4_3",
        "num_outputs": 1
      },
      "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/dev",
  "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": 25,
    "usd": "0.025",
    "charged": 25,
    "refunded": 0
  },
  "input": {
    "prompt": "A red fox trots through fresh snow at sunrise, soft golden light, shallow depth of field, telephoto lens",
    "image_size": "landscape_4_3",
    "num_outputs": 1
  },
  "output": {
    "images": [
      {
        "url": "https://content.doitong.com/dev-api/2026/10/20/req_8k2m4q7x1z9c3v5b6n0p2r4t/0-output.jpeg",
        "width": 1024,
        "height": 768,
        "content_type": "image/jpeg"
      }
    ],
    "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, width, height, content_type} | Informations de fichier pour les images générées. |
| `timings` | object |  |
| `seed` | integer | Graine de génération d’image, incluant la valeur choisie aléatoirement si l’entrée n’a pas fourni de graine; sinon, elle répète la valeur fournie. |
| `has_nsfw_concepts` | array of boolean | Indique si des concepts NSFW apparaissent dans les images générées. |
| `prompt` | string | Invite utilisée pendant la génération d’image. |

## Related models

- [FLUX.1 \[schnell\]](https://doitong.com/developers/models/flux/schnell.md) (`flux/schnell`): $0.003 / megapixel
- [FLUX.1 \[dev\] Redux](https://doitong.com/developers/models/flux/dev/redux.md) (`flux/dev/redux`): $0.025 / megapixel
- [FLUX.1 \[schnell\] Redux](https://doitong.com/developers/models/flux/schnell/redux.md) (`flux/schnell/redux`): $0.025 / megapixel
- [FLUX.1 · Dev · Image to Image](https://doitong.com/developers/models/flux/dev/image-to-image.md) (`flux/dev/image-to-image`): $0.09 / image
- [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

## Links

- HTML page: https://doitong.com/developers/models/flux/dev
- 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/dev
- Errors: https://doitong.com/developers/docs/errors
- Model details as JSON: https://api.doitong.com/v1/models/flux/dev