# FLUX.1 [dev] API

> Mô hình FLUX chủ lực có trọng số mở, sắc nét hơn và bám sát lời nhắc dài tốt hơn schnell.

Mô hình FLUX 12 tỷ tham số được chưng cất theo hướng dẫn, với lịch lấy mẫu đầy đủ (mặc định 28 bước, điều chỉnh từ 1 đến 50) và thang hướng dẫn có thể tinh chỉnh. Mô hình tuân theo lời nhắc chi tiết và kết xuất bàn tay, khuôn mặt cùng văn bản ngắn tốt hơn đáng kể so với biến thể schnell với mức giá cao hơn. Hỗ trợ kích thước đặt sẵn hoặc tùy chỉnh, tối đa bốn hình ảnh mỗi yêu cầu, đầu ra JPEG hoặc 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/vi/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 |  |  | Lời nhắc định hướng việc tạo sinh hình ảnh. |
| `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` | Kích thước hình ảnh được tạo. |
| `num_inference_steps` |  | integer | no | `28` | 1 – 50 | Số bước suy luận cần chạy. |
| `seed` |  | integer \| null | no |  |  | Seed cho hình ảnh có thể tái tạo: lời nhắc và seed giống hệt nhau sẽ tạo ra hình ảnh giống hệt khi phiên bản mô hình không đổi. |
| `guidance_scale` |  | number | no | `3.5` | 1 – 20 | Mức độ tuân thủ lời nhắc khi chọn hình ảnh, được biểu thị bằng CFG (Classifier Free Guidance). |
| `num_images` | `num_outputs` | integer | no | `1` | 1 – 4 | Số lượng hình ảnh yêu cầu tạo sinh. |
| `output_format` |  | enum (string) | no | `jpeg` | `jpeg`, `png` | Định dạng tệp của hình ảnh kết quả. |
| `acceleration` |  | enum (string) | no | `none` | `none`, `regular`, `high` | Tăng tốc tạo sinh; thiết lập cao hơn làm giảm thời gian cần để tạo kết quả. |

## 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} | Thông tin tệp của các hình ảnh được tạo. |
| `timings` | object |  |
| `seed` | integer | Seed tạo sinh hình ảnh, bao gồm giá trị được chọn ngẫu nhiên nếu đầu vào không cung cấp seed; nếu không, lặp lại giá trị đã cung cấp. |
| `has_nsfw_concepts` | array of boolean | Cho biết các khái niệm NSFW có xuất hiện trong hình ảnh được tạo sinh hay không. |
| `prompt` | string | Lời nhắc được sử dụng trong quá trình tạo sinh hình ảnh. |

## 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