QuickstartMedia Gen REST APIsGenerateImages

Stable Diffusion 3 API

Generate an image using a Stable Diffusion 3 (SD3 Medium), a 2 billion parameter model. It excels in photorealism, processes complex prompts, and generates clear text.

OctoAI’s SD3 API supports both text-to-image and image-to-image use cases.

You need to create an OctoAI Authentication Token to access this API.

How to use

Invoke https://image.octoai.run/generate/sd3 endpoint with a POST request.

The headers of the request must include an Authentication Token in the authorization field. The accept header should be set to application/json to receive the image encoded as base64 in a JSON response.

Generating with a prompt: Commonly referred to as text-to-image, this mode generates an image from text alone. While the only required parameter is the prompt, it also supports a width and height parameter which can be used to control the aspect ratio of the generated image.

Generating with a prompt and an image: Commonly referred to as image-to-image, this mode also generates an image from text but uses an existing image as the starting point. The required parameters are:

  • prompt - text to generate the image from
  • init_image - the image to use as the starting point for the generation
  • strength - controls how much influence the image parameter has on the output image

For more details about all parameters, please see the request schema below.


The resolution of the generated image will be 1 megapixel. The default resolution is 1024x1024.


$0.03 per image, 30 steps, 1024X1024

Check Pricing Page for more details.

Request Details


Authorization (Required): Your OCTOAI_TOKEN
Content-Type (Required): Set to application/json


  • prompt (string [ 1 .. 10000 ] characters, Required): A string of text describing the image to generate. A strong, descriptive prompt that clearly defines elements, colors, and subjects will lead to better results.
  • negative_prompt (string, Optional): Text describing image traits to avoid during generation.
  • cfg_scale (double, Optional): Floating-point number represeting how closely to adhere to prompt description. Must be a positive number no greater than 50.0. Defaults to 12.
  • image_encoding (enum, Optional): Define which encoding process should be applied before returning the generated image(s). Allowed values: jpeg png
  • num_images (integer, Optional): Integer representing how many output images to generate with a single prompt/configuration. Defaults to 1. Allowed values: 1-16.
  • seed (union, Optional): Integer number or list of integers representing the seeds of random generators. Fixing random seed is useful when attempting to generate a specific image. Must be greater than 0 and less than 2^32.
  • steps (integer, Optional Defaults to 30): Integer representing how many steps of diffusion to run. Must be greater than 0 and less than or equal to 200.
  • init_image (string, Optional): The image (encoded in b64 string) to use as the starting point for the generation. This parameter is for Image-to-Image generation.
  • strength (double,Optional): Floating-point number indicating how much creative the Image to Image generation mode should be. Must be greater than 0 and less than or equal to 1.0. Defaults to 0.8. This parameter is for Image-to-Image generation.
  • height (integer, Optional): Integer representing the height of image to generate. Default to 1024.
  • width (integer, Optional): Integer representing the width of image to generate. Default to 1024.

Supported Output Resolutions (Width x Height) are as follows:


(1536, 640), (768, 1344), (832, 1216), (1344, 768),
(1152, 896),(640, 1536), (1216, 832), (896, 1152), (1024, 1024)

Request Examples

$curl --location 'https://image.octoai.run/generate/sd3' \
>--header 'Authorization: Bearer <ENTER_OCTOAI_TOKEN>' \
>--header 'Content-Type: application/json' \
>--data '{
> "prompt": "In the style of a artistic children'\''s coloring book stands an extremely detailed mythical unicorn squirrel in an enchanted forest! A tiny woodland critter with a coat that sparkles like a rainbow dipped in glitter. Its fur is a magical medley of shimmering silver and pastel hues, catching the light in a dazzling display as the light hits its face. The unicord squirrel has a majestic horn spiraled like a candy cane and glowing with a soft, fairy-tale glow that lights up the forest at dusk. Its eyes are big, bright eyes twinkle like stars.",
> "negative_prompt": "",
> "seed":4275432097,
> "cfg_scale": 4,
> "steps": 30,
> "num_images": 1