llms.txt

FLUX.2 [klein] 9B

Image-to-image editing with FLUX.2 [klein] 9B from Black Forest Labs. Precise modifications using natural language descriptions and hex color control.

Overview

Endpoint: https://fal.run/fal-ai/flux-2/klein/9b/edit
Model ID: fal-ai/flux-2/klein/9b/edit
Category: image-to-image
Kind: inference

Pricing

Requests cost $0.011 per megapixel of input and output. Input images will be resized to 1MP. For example, a 1024×1024 generation with a 512×512 input image will cost $0.022 (1 MP input + 1 MP output, each costing $0.011).

For more details, see fal.ai pricing.

API Information

This model can be used via our HTTP API or more conveniently via our client libraries. See the input and output schema below, as well as the usage examples.

Input Schema

The API accepts the following input parameters:

prompt (string, required): The prompt to edit the image.
- Examples: "Turn this into a realistic image"
seed (integer, optional): The seed to use for the generation. If not provided, a random seed will be used.
num_inference_steps (integer, optional): The number of inference steps to perform. Default value: 4
- Default: 4
- Range: 4 to 8
image_size (ImageSize | Enum, optional): The size of the generated image. If not provided, uses the input image size.
- One of: ImageSize | Enum
- Examples: {"height":1152,"width":2016}
num_images (integer, optional): The number of images to generate. Default value: 1
- Default: 1
- Range: 1 to 4
sync_mode (boolean, optional): If True, the media will be returned as a data URI. Output is not stored when this is True.
- Default: false
enable_safety_checker (boolean, optional): If set to true, the safety checker will be enabled. Disabling it requires account authorization; unauthorized requests are always checked, and images flagged as unsafe are returned as black images. Default value: true
- Default: true
output_format (OutputFormatEnum, optional): The format of the generated image. Default value: "png"
- Default: "png"
- Options: "jpeg", "png", "webp"
image_urls (list<string>, required): The URLs of the images for editing. A maximum of 4 images are allowed.
- Array of string
- Examples: ["https://v3b.fal.media/files/b/0a8a69d5/kkXxFfj1QeVtw35kxy5Py_1a7e3511-bd2c-46be-923a-8e6be2496f12.png"]

Required Parameters Example:

{
  "prompt": "Turn this into a realistic image",
  "image_urls": [
    "https://v3b.fal.media/files/b/0a8a69d5/kkXxFfj1QeVtw35kxy5Py_1a7e3511-bd2c-46be-923a-8e6be2496f12.png"
  ]
}

Full Example:

{
  "prompt": "Turn this into a realistic image",
  "num_inference_steps": 4,
  "image_size": {
    "height": 1152,
    "width": 2016
  },
  "num_images": 1,
  "enable_safety_checker": true,
  "output_format": "png",
  "image_urls": [
    "https://v3b.fal.media/files/b/0a8a69d5/kkXxFfj1QeVtw35kxy5Py_1a7e3511-bd2c-46be-923a-8e6be2496f12.png"
  ]
}

Output Schema

The API returns the following output format:

images (list<ImageFile>, required): The generated images
- Array of ImageFile
timings (Timings, required)
seed (integer, required): Seed of the generated Image. It will be the same value of the one passed in the input or the randomly generated that was used in case none was passed.
has_nsfw_concepts (list<boolean>, required): Whether the generated images contain NSFW concepts.
- Array of boolean
prompt (string, required): The prompt used for generating the image.

Example Response:

{
  "images": [
    {
      "url": "",
      "content_type": "image/png",
      "file_name": "z9RV14K95DvU.png",
      "file_size": 4404019
    }
  ],
  "prompt": ""
}

Usage Examples

cURL

curl --request POST \
  --url https://fal.run/fal-ai/flux-2/klein/9b/edit \
  --header "Authorization: Key $FAL_KEY" \
  --header "Content-Type: application/json" \
  --data '{
     "prompt": "Turn this into a realistic image",
     "image_urls": [
       "https://v3b.fal.media/files/b/0a8a69d5/kkXxFfj1QeVtw35kxy5Py_1a7e3511-bd2c-46be-923a-8e6be2496f12.png"
     ]
   }'

Python

Ensure you have the Python client installed:

pip install fal-client

Then use the API client to make requests:

import fal_client

def on_queue_update(update):
    if isinstance(update, fal_client.InProgress):
        for log in update.logs:
           print(log["message"])

result = fal_client.subscribe(
    "fal-ai/flux-2/klein/9b/edit",
    arguments={
        "prompt": "Turn this into a realistic image",
        "image_urls": ["https://v3b.fal.media/files/b/0a8a69d5/kkXxFfj1QeVtw35kxy5Py_1a7e3511-bd2c-46be-923a-8e6be2496f12.png"]
    },
    with_logs=True,
    on_queue_update=on_queue_update,
)
print(result)

JavaScript

Ensure you have the JavaScript client installed:

npm install --save @fal-ai/client