stepfun-ai/step1x-edit API

This document introduces the input and output parameters of the stepfun-ai/step1x-edit model API, for referencing field meanings during interface use.

Request Parameters

Request Body

Field Name	Type	Required	Default Value	Description
prompt	string	Yes	-	Prompt word
model	string	Yes	-	The model name used for this request, which here is `stepfun-ai/step1x-edit`.
image	string	Yes	-	Base64 data or image link http://xxx
n	int	Optional	1	The number of images generated, ranging from 1 to 4
strength	float	Optional	0.8	The degree of transformation referenced by the image, ranging from 0 to 1
seed	int	Optional	-1	Random seed, used to control the randomness of the model’s generated content. For consistent content, use the same seed value.
steps	int	Optional	20	Number of inference steps, ranging from 1 to 50
guidance_scale	float	Optional	2.5	The consistency between the model output and the prompt, i.e., the degree of freedom of the generated image; the larger the value, the lower the degree of freedom, and the stronger the correlation with the user’s prompt. Range [1, 10].
negative_prompt	string	Optional	-	Negative prompt word, used to specify content you do not wish to appear in the generated image
response_format	string	Optional	”url”	Specify the format for returning the generated image, default is `url`, options include `b64_json`

Response Parameters

Field Name	Type	Description
created	`integer`	Unix timestamp (in seconds) of when the request was created.
data	`array`	Information about the output image, including the URL for downloading the image or Base64. • If the format is specified as url, subfield is url; • If the format is specified as b64_json, subfield is b64_json. Note: The link will expire 7 days after generation, so be sure to save the image promptly.
error	`Object`	Error information object
error.code	`string`	Error code
error.message	`string`	Error message
error.param	`string`	Request id

Example

OPENAI Compatible Interface

POST https://api.umodelverse.ai/v1/images/generations

Synchronous Request


curl --location 'https://api.umodelverse.ai/v1/images/generations' \
--header "Authorization: Bearer $MODELVERSE_API_KEY" \
--header 'Content-Type: application/json' \
--data '{
    "model": "stepfun-ai/step1x-edit",
    "prompt": "Convert to quick pencil sketch",
    "image": "data:image/png;base64,{image_base64_string}",
    "negative_prompt": "blurry, low quality"
}'


import os
from openai import OpenAI
 
client = OpenAI(
    base_url=os.getenv("BASE_URL", "https://api.umodelverse.ai/v1"),
    api_key=os.getenv("API_KEY", "$MODELVERSE_API_KEY")
)
 
response = client.images.generate(
    model="stepfun-ai/step1x-edit",
    prompt="Convert to quick pencil sketch",
    extra_body={
        "image": "data:image/png;base64,{image_base64_string}",
        "negative_prompt": "blurry, low quality"
    }
)
 
print(response.data[0].url)

Response


{
  "created": 1750667997,
  "data": [
    {
      "url": "https://xxxxx/xxxx.png",
      "b64_json": "data:image/png;base64,{image_base64_string}"
    }
  ],
  "usage": {
    "input_tokens_details": {}
  }
}


{
  "error": {
    "message": "error_message",
    "type": "error_type",
    "param": "request_id",
    "code": "error_code"
  }
}