Flux Klein 4B

Lightweight and efficient text-to-image generation with excellent speed-to-quality ratio

flux-klein-4b is a compact 4 billion parameter model based on Flux architecture, optimized for fast inference while maintaining high image quality. It's ideal for applications requiring quick turnaround times without sacrificing visual fidelity.

Rate Limit: 150 requests per minute

Pricing:

`output_megapixels`	Price
`0.25`, `0.5`, `1` (default)	$0.002 / image
`2`	$0.003 / image
`4`	$0.005 / image

Category: Text-to-Image Generation

Quickstart

Asynchronous Request (Default)

curl -X POST 'https://api.pruna.ai/v1/predictions' \
  -H 'Content-Type: application/json' \
  -H 'apikey: YOUR_API_KEY' \
  -H 'Model: flux-klein-4b' \
  -d '{
    "input": {
      "prompt": "A serene mountain landscape at dawn with mist rolling through the valleys",
      "aspect_ratio": "16:9"
    }
  }'

Response:

{
  "id": "1zww7deyssrme0csqwr90phzzr",
  "model": "flux-klein-4b",
  "input": { ... },
  "get_url": "https://api.pruna.ai/v1/predictions/status/1zww7deyssrme0csqwr90phzzr"
}

Check status and get results:

curl -X GET 'https://api.pruna.ai/v1/predictions/status/1zww7deyssrme0csqwr90phzzr' \
  -H 'apikey: YOUR_API_KEY'

Synchronous Request (Try-Sync)

curl -X POST 'https://api.pruna.ai/v1/predictions' \
  -H 'Content-Type: application/json' \
  -H 'apikey: YOUR_API_KEY' \
  -H 'Model: flux-klein-4b' \
  -H 'Try-Sync: true' \
  -d '{
    "input": {
      "prompt": "A serene mountain landscape at dawn with mist rolling through the valleys",
      "aspect_ratio": "16:9"
    }
  }'

Response (if completed within 60 seconds):

{
  "status": "succeeded",
  "generation_url": "/v1/predictions/delivery/xezq/abc123.../output.jpg"
}

Parameters

Required Parameters

Parameter	Type	Description
`prompt`	string	Text description of the image you want to generate

Optional Parameters

Parameter	Type	Default	Description
`aspect_ratio`	string	"1:1"	Aspect ratio of output. Options: "1:1", "16:9", "21:9", "3:2", "2:3", "4:5", "5:4", "3:4", "4:3", "9:16", "9:21", "match_input_image"
`images`	array	[]	List of input images for image-to-image generation. Maximum 5 images. Must be jpeg, png, gif, or webp
`output_megapixels`	string	"1"	Resolution of the output image in megapixels. Options: "0.25", "0.5", "1", "2", "4"
`go_fast`	boolean	false	Run faster predictions with additional optimizations
`seed`	integer	random	Random seed for reproducible generation
`output_format`	string	"jpg"	Output format: "png", "jpg", or "webp"
`output_quality`	integer	95	Quality for jpg/webp (0-100)
`disable_safety_checker`	boolean	false	Disable safety checker for generated images