API reference · Stability AI

stability-ai/fast-sdxl/image-to-image

Integrate this model through SandBase's unified API, with production-ready schemas and examples.

IMAGEAsyncOpen model

Production endpoint

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OpenAI-compatible endpoint with unified authentication and usage tracking.

POSThttps://api.sandbase.ai/v1/run

Model IDstability-ai/fast-sdxl/image-to-image

Input Schema

15 parameters · 2 required · 13 optional

Parameter	Type	Required	Description
`image`	string	Required	The URL of the image to use as a starting point for the generation.
`prompt`	string	Required	The prompt to use for generating the image. Be as descriptive as possible for best results.
`seed`	integer	Optional	The same seed and the same prompt given to the same version of Stable Diffusion will output the same image every time. · Default: null
`loras`	object[]	Optional	The list of LoRA weights to use. · Default: []
`format`	string	Optional	The format of the generated image. · Options: jpeg, png · Default: "jpeg" jpegpng
`strength`	number	Optional	determines how much the generated image resembles the initial image · Min: 0.05 · Max: 1 · Default: 0.95
`embeddings`	object[]	Optional	The list of embeddings to use. · Default: []
`request_id`	string	Optional	An id bound to a request, can be used with response to identify the request itself. · Default: ""
`crop_output`	boolean	Optional	If set to true, the output cropped to the proper aspect ratio after generating. · Default: false
`aspect_ratio`	string	Optional	The aspect ratio of the generated image. · Options: 21:9, 16:9, 3:2, 4:3, 5:4, 1:1, 4:5, 3:4, 2:3, 9:16 21:916:93:24:35:41:14:53:42:39:16
`expand_prompt`	boolean	Optional	If set to true, the prompt will be expanded with additional prompts. · Default: false
`guidance_scale`	number	Optional	The CFG (Classifier Free Guidance) scale is a measure of how close you want the model to stick to your prompt when looking for a related image to show you. · Min: 0 · Max: 20 · Default: 7.5
`num_inference_steps`	integer	Optional	The number of inference steps to perform. · Min: 1 · Max: 65 · Default: 25
`preserve_aspect_ratio`	boolean	Optional	If set to true, the aspect ratio of the generated image will be preserved even if the image size is too large. However, if the image is not a multiple of 32 in width or height, it will be resized to the nearest multiple of 32. By default, this snapping to the nearest multiple of 32 will not preserve the aspect ratio. Set crop_output to True, to crop the output to the proper aspect ratio after generating. · Default: false
`safety_checker_version`	string	Optional	The version of the safety checker to use. v1 is the default CompVis safety checker. v2 uses a custom ViT model. · Options: v1, v2 · Default: "v1" v1v2

Output Schema

Field	Type	Description
`id`	string	Unique identifier for the generation task
`status`	string	Task status: pending, running, completed, failed, timeout
`model`	string	Model used for the generation
`outputs`	array	Array of output items
`outputs[].url`	string	URL of the generated artifact
`outputs[].content_type`	string	MIME type (e.g. image/png, video/mp4)
`error`	object \| null	Error details if failed, null on success
`error.type`	string	Machine-readable error type code
`error.message`	string	Human-readable error description

Async Workflow

This model uses asynchronous execution. Submit a request and poll for the result.

Submit — POST to /v1/run, receive an id
Poll — GET /v1/run/{id} until status is completed, failed, or timeout
Retrieve — Read outputs from the completed response

Code Examples

Ready-to-run snippets

# Step 1: Submit
curl -X POST https://api.sandbase.ai/v1/run \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -d '{
  "model": "stability-ai/fast-sdxl/image-to-image",
  "seed": null,
  "image": "https://fal-cdn.batuhan-941.workers.dev/files/tiger/IExuP-WICqaIesLZAZPur.jpeg",
  "loras": [],
  "format": "jpeg",
  "prompt": "an island near sea, with seagulls, moon shining over the sea, light house, boats int he background, fish flying over the sea",
  "strength": 0.95,
  "embeddings": [],
  "request_id": "",
  "crop_output": false,
  "expand_prompt": false,
  "guidance_scale": 7.5,
  "num_inference_steps": 25,
  "preserve_aspect_ratio": false,
  "safety_checker_version": "v1"
}'

# Step 2: Poll result (replace <id>)
curl https://api.sandbase.ai/v1/run/<id> \
  -H "Authorization: Bearer YOUR_API_KEY"

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