BiRefNetFastUltra

BiRefNet

State-of-the-art open-source background removal. BiRefNet's high-fidelity dichotomous image segmentation delivers excellent edge quality on hair, fur, and fine details.

5 credits

per image

State-of-the-art segmentation quality

Excellent edges on hair, fur, and fine details

Adjustable processing resolution

Simple one-input API

Open-source (research-backed BiRefNet)

Run it right now

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

Use with AI Assistant

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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": "men1scus/birefnet",
  "input": {
    "image": "https://example.com/portrait.jpg"
  }
}'

Parameters

Parameter	Type	Required	Default	Description
`image`	string	Yes	-	Input image to remove the background from
`resolution`	string	No	-	Processing resolution in WxH format, e.g. '1024x1024'. Empty uses the default

How to Provide File Input

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

Recommended

Direct Upload (Multipart)

Attach files directly to POST /v1/predictions/upload. No separate upload step needed.

curl -X POST "https://api.core.today/v1/predictions/upload" \
  -H "X-API-Key: cdt_your_api_key" \
  -F "model=men1scus/birefnet" \
  -F 'input={"prompt":"your prompt here"}' \
  -F "file:image=@your_file.png"

Image URL

Pass a publicly accessible URL directly. You can also use file_url from the Storage API.

{
  "model": "men1scus/birefnet",
  "input": {
    "prompt": "your prompt here",
    "image": "https://example.com/image.jpg"
  }
}

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

High-Fidelity Portrait Cutout

Remove the background from a portrait with fine hair details

curl -X POST "https://api.core.today/v1/predictions" \
  -H "Content-Type: application/json" \
  -H "X-API-Key: cdt_your_api_key" \
  -d '{
  "model": "men1scus/birefnet",
  "input": {
    "image": "https://example.com/portrait.jpg"
  }
}'