> ## Documentation Index
> Fetch the complete documentation index at: https://docs.jiekou.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# FLUX.1 Kontext Dev

FLUX.1 Kontext Dev is a model designed for editing needs, maintaining high efficiency and speed while improving prompt adherence and font generation consistency.

## Request Headers

<ParamField header="Content-Type" type="string" required={true}>
  Enum value: `application/json`
</ParamField>

<ParamField header="Authorization" type="string" required={true}>
  Bearer authentication format: Bearer \{\{API Key}}.
</ParamField>

## Request Body

<ParamField body="prompt" type="string" required={true}>
  The prompt used to generate the image.
</ParamField>

<ParamField body="images" type="string[]" required={false}>
  A list of images used to generate the image. Supports up to 4 images.
</ParamField>

<ParamField body="fast_mode" type="boolean" required={false}>
  Whether to enable ultra-fast mode. When enabled, generation is faster, but quality may be reduced and the price is lower.

  Default value: `false`.
</ParamField>

<ParamField body="size" type="string" required={false}>
  The size of the generated media (pixels, width\*height). Range for each dimension: \[256 \~ 1536].
</ParamField>

<ParamField body="num_inference_steps" type="integer" required={false}>
  Number of inference steps. Default value is 28. Value range: \[1 \~ 50].
</ParamField>

<ParamField body="guidance_scale" type="number" required={false}>
  Guidance scale, used to control generation. Default value is 2.5. Value range: \[1.0 \~ 20.0].
</ParamField>

<ParamField body="num_images" type="integer" required={false}>
  The number of images to generate. Default value is 1. Value range: \[1 \~ 4].
</ParamField>

<ParamField body="seed" type="integer" required={false}>
  Random seed. Default value is -1; -1 indicates using a random seed. Value range: \[-1 \~ 2147483647].
</ParamField>

<ParamField body="output_format" type="string" required={false}>
  The output image format. Default value is jpeg.<br />
  Options: `jpeg`, `png`, `webp`
</ParamField>

## Response Information

<ResponseField name="task_id" type="string" required={true}>
  The task\_id of the asynchronous task. You should use this task\_id to request the [Get Task Result API](/en/docs/models/reference-get-async-task-result) to retrieve the generation result.
</ResponseField>