# FLUX.1 Kontext [dev] API

> Édition d'image Kontext à poids ouverts, fondée sur des instructions, avec réglage de la vitesse

Modifie une image de `image_url` en suivant un `prompt` textuel. `resolution_mode` peut faire correspondre l'entrée, choisir automatiquement ou imposer un ratio tel que 16:9 ou 9:21. `acceleration` propose none, regular ou high, et le modèle prend en charge 10 à 50 étapes et jusqu'à 4 sorties.

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

## Pricing

Price: **$0.025 / image**. Estimated from the typical cost of one run, per output (`num_images`). The quote is exactly what the run charges.

The full example input below costs $0.025 = 25 API credits (1 image × 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-kontext/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 |  |  | Prompt décrivant les modifications de l’image. |
| `image_url` | `image` | string (image URL) | yes |  |  | URL de l’image à modifier, avec une largeur et une hauteur limitées chacune à 14142px et un délai d’expiration de 20 secondes. |
| `num_inference_steps` |  | integer | no | `28` | 10 – 50 | Nombre d’étapes d’inférence à exécuter. |
| `seed` |  | integer \| null | no |  |  | Seed pour des images reproductibles : un prompt et un seed identiques produisent une image identique lorsque la version du modèle est inchangée. |
| `guidance_scale` |  | number | no | `2.5` | 1 – 20 | Force d'adhérence au prompt pour la sélection d'image, exprimée comme CFG (Classifier Free Guidance). |
| `num_images` | `num_outputs` | integer | no | `1` | 1 – 4 | Nombre d'images demandé pour la génération. |
| `enable_safety_checker` |  | boolean | no | `true` |  | Vérification de sécurité qui renvoie des images noires à la place des images signalées comme non sûres. La valeur true active la vérification ; false la désactive uniquement pour les comptes autorisés, tandis que les requêtes sans autorisation sont vérifiées dans tous les cas. |
| `output_format` |  | enum (string) | no | `jpeg` | `jpeg`, `png` | Format utilisé pour la sortie. |
| `acceleration` |  | enum (string) | no | `none` | `none`, `regular`, `high` | Accélération de la génération ; des paramètres plus élevés réduisent le temps nécessaire pour générer les résultats. |
| `resolution_mode` |  | enum (string) | no | `match_input` | `auto`, `match_input`, `1:1`, `16:9`, `21:9`, `3:2`, `2:3`, `4:5`, `5:4`, `3:4`, `4:3`, `9:16`, `9:21` | Choisissez la manière dont la modification d’image détermine la résolution de sortie : `match_input` tente de conserver les dimensions d’entrée, mais les ajuste pour respecter les exigences du modèle, notamment les multiples de 16 et les limites de taille prises en charge. Pour la plupart des usages, `auto` est recommandé, car il utilise les résolutions sur lesquelles le modèle a été entraîné et sélectionne la taille prédéfinie optimale selon le rapport hauteur/largeur de l’entrée. Quelques rapports hauteur/largeur explicites sont également disponibles. |

File parameters (`image`) take a public `https://` URL, a `data:` URI up to 10 MB, or the `file_url` of an upload from `POST /files`.

## Example input

Required parameters only:

```json
{
  "prompt": "A red fox trots through fresh snow at sunrise, soft golden light, shallow depth of field",
  "image": "https://content.doitong.com/images/showcase/v3/gen_fox_cartoon.jpg"
}
```

A fuller example:

```json
{
  "prompt": "A red fox trots through fresh snow at sunrise, soft golden light, shallow depth of field",
  "image_url": "https://content.doitong.com/images/showcase/v3/gen_fox_cartoon.jpg"
}
```

## 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-kontext/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",
    "image_url": "https://content.doitong.com/images/showcase/v3/gen_fox_cartoon.jpg"
  }'

# 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-kontext/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",
    "image_url": "https://content.doitong.com/images/showcase/v3/gen_fox_cartoon.jpg"
  }),
});
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",
    "image_url": "https://content.doitong.com/images/showcase/v3/gen_fox_cartoon.jpg",
}

# Run the model; wait up to 20 s for the finished result in the same call
r = requests.post(API + "/run/flux-kontext/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-kontext/dev",
      "input": {
        "prompt": "A red fox trots through fresh snow at sunrise, soft golden light, shallow depth of field",
        "image_url": "https://content.doitong.com/images/showcase/v3/gen_fox_cartoon.jpg"
      },
      "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-kontext/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",
    "image_url": "https://content.doitong.com/images/showcase/v3/gen_fox_cartoon.jpg"
  },
  "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 | Seed de génération d'images, y compris la valeur choisie aléatoirement si l'entrée n'en fournissait pas ; sinon, il reprend la valeur fournie. |
| `has_nsfw_concepts` | array of boolean | Indique si des concepts NSFW apparaissent dans les images générées. |
| `prompt` | string | Prompt utilisé pendant la génération d'images. |

## Related models

- [FLUX.1 Kontext \[max\]](https://doitong.com/developers/models/flux-pro/kontext/max.md) (`flux-pro/kontext/max`): $0.08 / image
- [FLUX.1 Kontext \[pro\]](https://doitong.com/developers/models/flux-pro/kontext.md) (`flux-pro/kontext`): $0.04 / image
- [FLUX.1 Kontext · Max · Multi](https://doitong.com/developers/models/flux-pro/kontext/max/multi.md) (`flux-pro/kontext/max/multi`): $0.08 / image
- [FLUX.1 Kontext · Max · Text to Image](https://doitong.com/developers/models/flux-pro/kontext/max/text-to-image.md) (`flux-pro/kontext/max/text-to-image`): $0.08 / image
- [FLUX.1 Kontext · Multi](https://doitong.com/developers/models/flux-pro/kontext/multi.md) (`flux-pro/kontext/multi`): $0.04 / image
- [FLUX.1 Kontext · Text to Image](https://doitong.com/developers/models/flux-pro/kontext/text-to-image.md) (`flux-pro/kontext/text-to-image`): $0.04 / image
- [GPT Image 2.5 Edit](https://doitong.com/developers/models/openai/gpt-image-2.5/flare/edit.md) (`openai/gpt-image-2.5/flare/edit`): from $0.12 / image
- [Nano Banana 2 Edit](https://doitong.com/developers/models/nano-banana-2/edit.md) (`nano-banana-2/edit`): from $0.06 / image

## Links

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