Black Forest Labs/flux-1-dev/Released Aug 2025

FLUX.1 [dev]

Open text-to-image with editing tools

Fine-tunable
Image

About FLUX.1 [dev]

black-forest-labs/FLUX.1-dev is a 12 billion parameter image generation model (rectified flow transformer, guidance-distilled) designed for non-commercial, research, and personal use.

It excels in generating high-quality, diverse images from text prompts, with strong prompt adherence and competitive performance on challenging details such as hands and faces. Its open weights and efficiency make it particularly valuable for researchers and developers who need transparency, adaptability, and the ability to fine-tune for specialized domains.

Some other noteworthy features of black-forest-labs/FLUX.1-dev include advanced control tools—such as inpainting, outpainting, structural guidance (depth and edge conditioning), and image remixing—enabling precise editing and re-creation of both real and generated images for research and creative workflows.

MetricValue
Parameter Count12 billion
Mixture of ExpertsNo
MultilingualNo
Quantized*No

*Quantization is specific to the inference provider and the model may be offered with different quantization levels by other providers.

Ready to build with FLUX.1 [dev]?

Try FLUX.1 [dev] in the Workbench to prompt it, compare outputs, and iterate on prompts without writing any code. When you're ready to ship, call the same model from our API and build your own apps on top of it.

curl -sSf -X POST https://hub.oxen.ai/api/ai/images/generate \
    -H "Content-Type: application/json" \
    -H "Authorization: Bearer $OXEN_API_KEY" \
    -d '{
  "model": "flux-1-dev",
  "prompt": "A beautiful landscape painting of a serene lake with mountains in the background",
  "negative_prompt": " ",
  "aspect_ratio": "16:9",
  "image_size": "optimize_for_quality",
  "num_inference_steps": 30,
  "guidance": 3,
  "output_format": "webp",
  "output_quality": 80,
  "disable_safety_checker": false
}'

Request parameters

Every field FLUX.1 [dev] accepts in the request body. See the API reference for response formats.

POSThttps://hub.oxen.ai/api/ai/images/generate
FieldTypeRequiredDefaultDescription
promptstringYes
Prompt for generated image
negative_promptstringNo
Negative prompt for generated image
aspect_ratiostringNo"16:9"
1:116:99:164:33:43:22:3
image_sizestringNo"optimize_for_quality"Image size for the generated image
optimize_for_qualityoptimize_for_speed
num_inference_stepsintegerNo30Number of denoising steps. Recommended range is 28-50, and lower number of steps produce lower quality outputs, faster.
Range: 150
guidancenumberNo3Guidance for generated image. Lower values can give more realistic images. Good values to try are 2, 2.5, 3 and 3.5
Range: 010
seedinteger
nullable
No
Random seed. Set for reproducible generation
output_formatstringNo"webp"Format of the output images
webpjpgpng
output_qualityintegerNo80Quality when saving the output images, from 0 to 100. 100 is best quality, 0 is lowest quality. Not relevant for .png outputs
Range: 0100
disable_safety_checkerbooleanNofalseDisable safety checker for generated images.