FLUX Schnell

This guide shows how to generate images using FLUX Schnell model via the Leonardo.AI REST API.

This guide shows how to generate images using FLUX Schnell model via the Leonardo.AI REST API.

Sample Request

curl --request POST \
     --url https://cloud.leonardo.ai/api/rest/v1/generations \
     --header 'accept: application/json' \
     --header 'authorization: Bearer <YOUR_API_KEY>' \
     --header 'content-type: application/json' \
     --data '{
       "modelId": "1dd50843-d653-4516-a8e3-f0238ee453ff",
       "contrast": 3.5,
       "prompt": "a photo of an orange cat playing with a tennis ball with the text FLUX",
       "num_images": 4,
       "width": 1024,
       "height": 1024,
       "styleUUID": "111dc692-d470-4eec-b791-3475abac4c46",
       "enhancePrompt": false
     }'

API Request Endpoint, Headers, Parameters

Endpoint

https://cloud.leonardo.ai/api/rest/v1/generations

Headers

--header "accept: application/json" \
--header "authorization: Bearer <YOUR_API_KEY>" \
--header "content-type: application/json"

Body Parameters

Parameter	Type	Definition
contrast	`number`	Required. Controls the contrast/detail level of generated images. Valid values: `[3, 3.5, 4]` where `3` corresponds to Low, `3.5` corresponds to Medium, and `4` corresponds to High in the web UI.
enhancePrompt	`string`	Optional. Enables prompt enhancement. Set to `true` for enhanced prompt behavior; when paired with `enhancePromptInstruction` it refines the prompt further.
enhancePromptInstruction	`string`	Optional. Provides additional instruction used alongside `enhancePrompt=true`.
height	`integer`	Optional. Height input resolution.
modelId	`string`	Required. UUID of the model to use. Set to `1dd50843-d653-4516-a8e3-f0238ee453ff`.
num_images	`integer`	Optional. Number of images to generate in the batch.
prompt	`string`	Required. Text prompt describing what image you want the model to generate.
seed	`integer`	Optional. Apply a fixed seed to maintain consistency across generation sets. The maximum seed number is `2147483638`.
styleUUID	`string`	Optional. UUID of a preset style that affects the aesthetic output. Refer to the table below for a list of UUIDs.
ultra	`boolean`	Optional. When `true`, enables Ultra generation mode.
width	`integer`	Optional. Width input resolution.

List of Style UUIDs

Preset Style	UUID
3D Render	`debdf72a-91a4-467b-bf61-cc02bdeb69c6`
Acrylic	`3cbb655a-7ca4-463f-b697-8a03ad67327c`
Anime General	`b2a54a51-230b-4d4f-ad4e-8409bf58645f`
Creative	`6fedbf1f-4a17-45ec-84fb-92fe524a29ef`
Dynamic	`111dc692-d470-4eec-b791-3475abac4c46`
Fashion	`594c4a08-a522-4e0e-b7ff-e4dac4b6b622`
Game Concept	`09d2b5b5-d7c5-4c02-905d-9f84051640f4`
Graphic Design 3D	`7d7c2bc5-4b12-4ac3-81a9-630057e9e89f`
Illustration	`645e4195-f63d-4715-a3f2-3fb1e6eb8c70`
None	`556c1ee5-ec38-42e8-955a-1e82dad0ffa1`
Portrait	`8e2bc543-6ee2-45f9-bcd9-594b6ce84dcd`
Portrait Cinematic	`4edb03c9-8a26-4041-9d01-f85b5d4abd71`
Ray Traced	`b504f83c-3326-4947-82e1-7fe9e839ec0f`
Stock Photo	`5bdc3f2a-1be6-4d1c-8e77-992a30824a2c`
Watercolor	`1db308ce-c7ad-4d10-96fd-592fa6b75cc4`

Image Guidance

Sample Request

curl --request POST \
     --url https://cloud.leonardo.ai/api/rest/v1/generations \
     --header 'accept: application/json' \
     --header 'authorization: Bearer <YOUR_API_KEY>' \
     --header 'content-type: application/json' \
     --data '{
       "height": 1024,
       "modelId": "1dd50843-d653-4516-a8e3-f0238ee453ff",
       "prompt": "Intricately swirling nebulas dance across a vividly colored galactic map",
       "width": 1024,
       "controlnets": [
             {
                 "initImageId": "06c4d15c-0d32-42b3-bec2-4e1d685d229f",
                 "initImageType": "GENERATED",
                 "preprocessorId": 232, // Content Reference
                 "strengthType": "High"
             }   
         ]
     }'

Body Parameters

Parameter	Type	Definition
initImageId	`string`	Leonardo Image ID.
initImageType	`string`	Whether an image is generated on or uploaded to the Leonardo platform. Accepts `GENERATED` or `UPLOADED`. To upload an image, see the recipe below.
preprocessorId	`integer`	ID corresponding to the type of image guidance. Refer to the table below for a list of preprocessor IDs.
strengthType	`string`	Strength of the input image guidance. Accepts `Low`, `Mid`, or `High`.

List of Preprocessor IDs

Model	Style Reference	Character Reference	Content Reference
Flux Schnell	298	n/a	232

Uploading Images

Updated 8 days ago