black-forest-labs/flux-2-klein-4b-base

Un-distilled version of FLUX.2 [klein]. Optimized for fine-tuning, customization, and post-training workflows

Capabilities

Seed

Community model (estimated from hardware time)

Name	Type	Description	Default	Constraints
`prompt` *	string	Text prompt for image generation.	`—`	—
`aspect_ratio`	string	Aspect ratio for the generated image. Use 'match_input_image' to match the aspect ratio of the first input image.	`"1:1"`	1:1 16:9 9:16 3:2 2:3 4:3 3:4 5:4 4:5 21:9 9:21 match_input_image
`disable_safety_checker`	boolean	Disable safety checker for generated images.	`false`	—
`go_fast`	boolean	Run faster predictions with additional optimizations.	`false`	—
`guidance`	number	Classifier-free guidance scale. Higher values produce images more closely related to the prompt.	`4`	min: 1, max: 10
`images`	array	List of input images for image-to-image generation. Maximum 5 images. Must be jpeg, png, gif, or webp.		—
`output_format`	string	Format of the output images	`"jpg"`	webp jpg png
`output_megapixels`	string	Resolution of the output image in megapixels	`"1"`	0.25 0.5 1 2 4
`output_quality`	integer	Quality when saving the output images, from 0 to 100. 100 is best quality, 0 is lowest quality. Not relevant for .png outputs.	`95`	min: 0, max: 100
`seed`	integer	Random seed. Set for reproducible generation	`—`	—

prompt required string

Text prompt for image generation.

aspect_ratio string

Aspect ratio for the generated image. Use 'match_input_image' to match the aspect ratio of the first input image.

Default: "1:1"

1:1 16:9 9:16 3:2 2:3 4:3 3:4 5:4 4:5 21:9 9:21 match_input_image

disable_safety_checker boolean

Disable safety checker for generated images.

Default: false

go_fast boolean

Run faster predictions with additional optimizations.

Default: false

guidance number

Classifier-free guidance scale. Higher values produce images more closely related to the prompt.

Default: 4 min: 1, max: 10

images array

List of input images for image-to-image generation. Maximum 5 images. Must be jpeg, png, gif, or webp.

Default:

output_format string

Format of the output images

Default: "jpg"

webp jpg png

output_megapixels string

Resolution of the output image in megapixels

Default: "1"

0.25 0.5 1 2 4

output_quality integer

Quality when saving the output images, from 0 to 100. 100 is best quality, 0 is lowest quality. Not relevant for .png outputs.

Default: 95 min: 0, max: 100

seed integer

Random seed. Set for reproducible generation

Version: 2289efa5ebba Updated: 6/26/2026 52.6K runs