# Flux 2 Flex API

> ᡳᠯᡤᠠᠨ ᡩᡝ ᠠᠰᡠᡥᠠᠨ ᡩᡝ ᡶᡳᠯᡤᠠᠨ ᠵᠠᠯᡠᠪᡠᡵᡝ, ᠵᠠᠮᡳᠨ ᠠᠯᡳ ᡠᠯᡤᠠᠨ ᠪᡝ ᠰᠣᠯᡤᠣᠮᡝ ᠠᠰᡠᡥᠠᠨ ᡳᠯᡤᠠᠨ ᡩᡝ ᡥᠠᠷᡤᠠᠨ ᠠᠯᡳ ᡥᡡᠯᡥᡝ ᡩᡝ ᠵᠠᠯᡠᠪᡠᡵᡝ

ᡳᠯᡤᠠᠨ `prompt` ᡳ ᡠᠮᡝᠰᡳ ᡳᠮᠠᡤᡝ ᠪᡳᠰᡳᡵᡝᠩᡤᡝ᠂ `num_inference_steps` ᡳ ᠵᠠᠯᠠᠨ ᠵᠠᠯᠠᠨ 2 ᡩᡝ 50 ᡳ ᠵᡝᡵᡤᡳ ᠵᠠᡴᡡᠨᡳ 28 ᡥᡝᠨᡝᠩᡤᡝ ᠮᠠᠨᡩᡝ ᠠᠮᠪᠠᠯᠠᠨ᠂ ᡩᠠᠮᡠ `guidance_scale` ᡳ 1.5 ᡩᡝ 10 ᡳ ᠵᡝᡵᡤᡳ ᠵᠠᡴᡡᠨᡳ 3.5 ᠪᡳᠰᡳᡵᡝᠩᡤᡝᠪᡝ ᡤᠠᠰᡥᠠᠨ ᠵᠠᡴᡡᠨᠠᠯᠠᠮᡝ ᡤᠠᠯᡠᠪᡳᠮᡝ᠂ square_hd, portrait_16_9 ᠮᡝ ᡳ landscape_4_3 ᠮᡝ ᡳ ᡠᠯᡤᡳᠰᡳ ᡩᡝᠨ ᡩᡝ ᡩᠠᠮᡠᠯᠠᠮᡝ ᡝᠯᡝᠮᡝ ᠣᠮᠪᡳ᠃ ᠮᡠᠰᡝ jpeg ᡳ ᡝᠮᡠ png ᠪᡝ ᡩᠠᠯᠵᡳᠮᠪᡳ᠂ `seed` ᠵᡝᠯᡳ ᠵᠠᠯᡳᠨ ᠣᠮᡝ ᡳᠯᡤᠠᠨ ᠵᠠᠯᠠᠨ ᠪᡝ ᡤᡝᠯᡳᠮᡝ ᠵᠠᠯᠠᠨᠠᠮᠪᡳ᠃

- Model id: `flux-2-flex`
- Made by: Black Forest Labs
- Category: Text to Image
- Output: image
- Price per megapixel of your output image: $0.05 / megapixel of output image (cheapest run $0.05 (50 API credits))
- Run: `POST https://api.doitong.com/v1/run/flux-2-flex`
- Quote: `POST https://api.doitong.com/v1/quote/flux-2-flex`
- Docs page: https://doitong.com/mnc/developers/models/flux-2-flex

## Pricing

Price: **$0.05 / megapixel of output image**. Price per megapixel of your output image: 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 $0.05 = 50 API credits (1 MP output image × $0.05).

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-2-flex` 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

| Parameter | Canonical name | Type | Required | Default | Allowed values / range | Description |
|---|---|---|---|---|---|---|
| `prompt` |  | string | yes |  |  | ᡤᠠᠳᠠᠨ ᠪᡠᠶᡝᠮᡝᠨᡳ ᡥᡡᠯᠠᠨ᠉ |
| `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` | ᠪᡠᠶᡝᠮᡝ ᡤᠠᠳᠠᠨ ᡳ ᡤᡳᡵᠠᠨ. |
| `seed` |  | integer \| null | no |  |  | ᠪᡠᠶᡝᠮᡝᠨᡳ ᠰᡝᠨᡩᡝᠨᡳ ᠵᠠᠯᡳᠨ᠉ |
| `safety_tolerance` |  | enum (string) | no | `2` | `1`, `2`, `3`, `4`, `5` | ᡳᠯᡳᠪᡠᡥᡝ ᠵᠠᠯᠠᠨ ᡳ ᡩᠠᠮᡠ ᠵᠠᠯᡳᠨ, 5 ᠠᠴᠠ 1 ᡥᡝᠴᡝ. |
| `enable_safety_checker` |  | boolean | no | `true` |  | ᡨᠣᡴᡨᠣᠨ ᠪᠠᡳᠴᠠᡵᠠ ᡝᠪᡠᠨ, ᠨᠠᡴᠠᠪᡠᡵᡝ ᡨᠣᡴᡨᠣᠪᡠᠨ ᠪᡝ ᡩᠠᠮᡠ ᡶᠠᠰᠠᡥᠠ ᡩᠠᠩᠰᡝ ᡩᡝ ᠠᠯᡳᠮᠪᡳ. ᡨᡝᡵᡝ ᡶᠠᠰᠠᡥᠠᠨ ᠠᡴᡡ ᡤᡝᠮᡠ ᡤᡝᡪᡳᠯᡝᠨ ᠪᡝ ᡨᠣᡴᡨᠣᠨ ᠪᠠᡳᠴᠠᠮᠪᡳ. |
| `output_format` |  | enum (string) | no | `jpeg` | `jpeg`, `png` | ᠪᡠᠶᡝᠮᡝ ᠵᡠᠴᡝᠨ ᡳ ᡶᡳᠯᡝ ᡳ ᠵᡠᠰᡝ᠉ |
| `guidance_scale` |  | number | no | `3.5` | 1.5 – 10 | ᠪᡠᠶᡝᠮᡝ ᡳ ᡥᡡᠰᡠᠨ ᠵᠠᠯᡳᠨ. |
| `num_inference_steps` |  | integer | no | `28` | 2 – 50 | ᠶᠠᠪᡠᠯᠠᡵᠠ ᡠᠯᡥᡳᠰᡠ ᠪᠣᡩᠣᡵᠣ ᠠᠯᡥᠠ ᡳ ᡨᠣᠨ. |

## 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.com/v1/run/flux-2-flex?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.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-2-flex?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.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",
}

# Run the model; wait up to 20 s for the finished result in the same call
r = requests.post(API + "/run/flux-2-flex", 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-2-flex",
      "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": "flux-2-flex",
  "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": 50,
    "usd": "0.05",
    "charged": 50,
    "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
      }
    ],
    "seed": 42
  },
  "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, content_type, file_name, file_size, width, height} | ᠮᠣᡩᡝᠯ ᠪᡠᠶᡝᠮᡝᠨᡳ ᠤᠯᡥᠠᠨ ᠤᠨᠠᠰᡳᠨ᠉ |
| `seed` | integer | ᠪᡠᠶᡝᠮᡝᠨᡳ ᠰᡝᠨᡩᡝᠨᡳ ᠵᠠᠯᡳᠨ᠉ |

## Related models

- [Flux 2 Flex · Edit](https://doitong.com/developers/models/flux-2-flex/edit.md) (`flux-2-flex/edit`): $0.334 / run
- [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/flux-2-flex
- 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-2-flex
- Errors: https://doitong.com/developers/docs/errors
- Model details as JSON: https://api.doitong.com/v1/models/flux-2-flex