ByteDanceMediumHigh

FLUX PuLID

PuLID identity customization on FLUX-dev: generate photorealistic portraits of a specific person from one face photo, with markedly higher fidelity than SDXL-based variants. Tune id_weight and start_step to balance likeness against prompt editability.

47 credits

46 credits x num_outputs (1-4 images)

FLUX-dev backbone for photorealistic, high-fidelity portraits

Tuning-free ID preservation from a single face photo

id_weight (0-3) controls how strongly the face is preserved

start_step trades fidelity (0) against prompt editability (4)

1-4 outputs per run, up to 1536px

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": "bytedance/flux-pulid",
  "input": {
    "main_face_image": "https://example.com/woman.png",
    "prompt": "a woman holding sign with glowing green text \"PuLID for FLUX\"",
    "width": 896,
    "height": 1152,
    "start_step": 4,
    "num_outputs": 4
  }
}'

Parameters

Parameter	Type	Required	Default	Description
`prompt`	string	No	portrait, color, cinematic	Text prompt to guide image generation
`main_face_image`	string	Yes	-	ID image for face generation
`negative_prompt`	string	No	bad quality, worst quality, text, signature, watermark, extra limbs, low resolution, partially rendered objects, deformed or partially rendered eyes, deformed, deformed eyeballs, cross-eyed, blurry	Enter a negative prompt to specify what to avoid in the image
`width`	integer	No	896	Output width in pixels (256-1536)
`height`	integer	No	1152	Output height in pixels (256-1536)
`num_steps`	integer	No	20	Number of denoising steps (1-20)
`start_step`	integer	No	0	Timestep to start inserting ID (0-10). 0 for highest fidelity, 4 for more editability
`guidance_scale`	number	No	4	Guidance scale for text prompt influence (1.0-10.0)
`id_weight`	number	No	1	Weight of the ID image influence (0.0-3.0)
`seed`	integer	No	-	Random seed (leave blank or -1 for random)
`true_cfg`	number	No	1	Set the Classifier-Free Guidance (CFG) scale. 1.0 uses standard CFG, while values >1.0 enable True CFG for more precise control over generation. Higher values increase adherence to the prompt at the cost of image quality.
`max_sequence_length`	integer	No	128	Set the max sequence length for prompt (T5), smaller is faster (128-512)
`output_format`	string	No	webp	Format of the output image pngjpgwebp
`output_quality`	integer	No	80	Set the quality of the output image for jpg and webp (1-100)
`num_outputs`	integer	No	1	Number of images to generate (1-4). Billed at 60 credits per image

How to Provide File Input

There are 3 ways to provide files for the main_face_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=bytedance/flux-pulid" \
  -F 'input={"prompt":"your prompt here"}' \
  -F "file:main_face_image=@your_file.png"

Image URL

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

{
  "model": "bytedance/flux-pulid",
  "input": {
    "prompt": "your prompt here",
    "main_face_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

Portrait Holding a Sign

FLUX handles in-scene text while keeping the face — four variations at once

curl -X POST "https://api.core.today/v1/predictions" \
  -H "Content-Type: application/json" \
  -H "X-API-Key: cdt_your_api_key" \
  -d '{
  "model": "bytedance/flux-pulid",
  "input": {
    "main_face_image": "https://example.com/woman.png",
    "prompt": "a woman holding sign with glowing green text \"PuLID for FLUX\"",
    "width": 896,
    "height": 1152,
    "start_step": 4,
    "num_outputs": 4
  }
}'

Maximum-Fidelity Headshot

start_step 0 and a single output for the closest likeness

curl -X POST "https://api.core.today/v1/predictions" \
  -H "Content-Type: application/json" \
  -H "X-API-Key: cdt_your_api_key" \
  -d '{
  "model": "bytedance/flux-pulid",
  "input": {
    "main_face_image": "https://example.com/face.jpg",
    "prompt": "portrait, color, cinematic, studio lighting, detailed face",
    "start_step": 0,
    "id_weight": 1,
    "num_outputs": 1
  }
}'