Black Forest LabsMediumHigh

FLUX.2 Dev

Development version of FLUX.2 with image editing capabilities and reference image support. Ideal for iterative design workflows and experimentation.

28 credits

per image (tiered by go_fast and custom size; input images billed per image)

Image editing capabilities

Reference image support

Balanced speed and quality

Great for iterative workflows

Cost-effective for development

Run it right now

Test this model instantly in the Console Playground — no code required

Use with AI Assistant

Copy usage instructions for Claude, ChatGPT, or other AI

llms.txtllms.txt ↗

Quick Start

curl -X POST "https://api.core.today/v1/predictions" \
  -H "Content-Type: application/json" \
  -H "X-API-Key: cdt_your_api_key" \
  -d '{
  "model": "black-forest-labs/flux-2-dev",
  "input": {
    "prompt": "A cozy reading nook with warm lighting, vintage armchair, floor-to-ceiling bookshelves, photorealistic interior design",
    "aspect_ratio": "4:3"
  }
}'

Parameters

Parameter	Type	Required	Default	Description
`prompt`	string	Yes	-	Text description of the image to generate
`input_images`	array	No	[]	Input images for image-to-image generation (max 4)
`go_fast`	boolean	No	true	Run faster predictions with additional optimizations
`aspect_ratio`	string	No	1:1	Aspect ratio for the generated image (use 'match_input_image' to match input) match_input_imagecustom1:116:93:22:34:55:49:163:44:3
`width`	integer	No	-	Width of the generated image in text-to-image mode. Only used when aspect_ratio=custom. Must be a multiple of 32 (if it's not, it will be rounded to nearest multiple of 32).
`height`	integer	No	-	Height of the generated image in text-to-image mode. Only used when aspect_ratio=custom. Must be a multiple of 32 (if it's not, it will be rounded to nearest multiple of 32).
`seed`	integer	No	-	Random seed for reproducibility
`output_format`	string	No	webp	Format of the output images webpjpgpng
`output_quality`	integer	No	80	Quality of output images (0-100)
`disable_safety_checker`	boolean	No	false	Disable safety checker for generated images.

How to Provide File Input

There are 3 ways to provide files for the input_images parameter:

Recommended

Image URL

Pass a publicly accessible URL directly. With the Storage API (POST /v1/files/upload-url) the file uploads straight to S3 (50MB per file) and you pass the returned file_url.

{
  "model": "black-forest-labs/flux-2-dev",
  "input": {
    "prompt": "your prompt here",
    "input_images": ["https://example.com/image.jpg"]
  }
}

Direct Upload (Multipart)

Attach files directly to POST /v1/predictions/upload. No separate upload step, but the bytes pass through the API server so the whole request is capped at 10MB.

curl -X POST "https://api.core.today/v1/predictions/upload" \
  -H "X-API-Key: cdt_your_api_key" \
  -F "model=black-forest-labs/flux-2-dev" \
  -F 'input={"prompt":"your prompt here"}' \
  -F "file:input_images=@your_file.png"

See the File Upload docs for more upload methods including Presigned URLs.

Common Parameters

Common parameters used when calling POST /v1/predictions.

Parameter	Type	Required	Default	Description
`model`	string	Yes	-	Model identifier
`input`	object	Yes	-	Object containing the model-specific parameters from the table above
`output_folder`	string	No	-	Folder path for output files (max 256 chars, '..' not allowed)
`webhook_url`	string	No	-	Webhook URL to call on completion
`is_public`	boolean	No	false	If true, output files are also available via permanent public URLs

Examples

Reference-based Generation

Generate an image guided by a reference

curl -X POST "https://api.core.today/v1/predictions" \
  -H "Content-Type: application/json" \
  -H "X-API-Key: cdt_your_api_key" \
  -d '{
  "model": "black-forest-labs/flux-2-dev",
  "input": {
    "prompt": "A cozy reading nook with warm lighting, vintage armchair, floor-to-ceiling bookshelves, photorealistic interior design",
    "aspect_ratio": "4:3"
  }
}'