ComfyUI Node
arkennemasis fal · Flux Subject · $0.04/MP
Super fast endpoint for the FLUX.1 [schnell] model with subject input capabilities, enabling rapid and high-quality image generation for personalization, specific styles, brand identities, and product-specific outputs. Pricing (from fal, 2026-09-29): $0.04 per megapixel (fal's billing unit). Model page: https://fal.ai/models/fal-ai/flux-subject Key: FAL_KEY in the .env next to run_nvidia_gpu.bat. Results are saved in output/fal/fal-ai_flux-subject/.
arkennemasis fal · Flux Subject · $0.04/MP
- image
- images
- image_paths
- seed
- timings
- prompt
- has_nsfw_concepts
- info
◄prompt►
◄image_sizesquare_hd►
◄image_size_width1024►
◄image_size_height1024►
◄num_inference_steps8►
◄seed-1►
◄guidance_scale3.50►
◄num_images1►
◄enable_safety_checkertrue►
◄output_formatpng►
◄max_cost_usd20.0►
◄reuse_identical_runtrue►
◄extra_json►
◄max_concurrent1►
Categoryarkennemasis/fal/Image/Flux
Inputs (15)
| Name | Type | Default | Description |
|---|---|---|---|
| prompt | STRING | The prompt to generate an image from. | |
| image | IMAGE | URL of image of the subject | |
| image_size | COMBO | square_hd | The size of the generated image. 'custom' uses the width and height below. |
| image_size_width | INT | 102416–14142 | Width in pixels when image_size is 'custom'. |
| image_size_height | INT | 102416–14142 | Height in pixels when image_size is 'custom'. |
| num_inference_steps | INT | 81–50 | The number of inference steps to perform. |
| seed | INT | -1-1–2147483647 | The same seed and the same prompt given to the same version of the model will output the same image every time. -1 leaves it to the model. |
| guidance_scale | FLOAT | 3.500–20 | The CFG (Classifier Free Guidance) scale is a measure of how close you want the model to stick to your prompt when looking for a related image to show you. |
| num_images | INT | 11–4 | The number of images to generate. |
| enable_safety_checker | BOOLEAN | true | If set to true, the safety checker will be enabled. Disabling it requires account authorization; unauthorized requests are always checked, and images flagged as unsafe are returned as black images. |
| output_format | COMBO | png | The format of the generated image. |
| max_cost_usdopt | FLOAT | 20.00–100000 | Safety cap. If the estimated cost of this run is above this many US dollars the node stops BEFORE sending anything to fal. 0 = no cap. |
| reuse_identical_runopt | BOOLEAN | true | If these exact inputs (the settings AND the same pictures/clips/audio) were already paid for and the files are still in output/fal, return them instead of paying again - also after a ComfyUI restart. Turn off for a fresh take with the same settings. |
| extra_jsonopt | STRING | Advanced: a JSON object merged into the request last, for any fal field this node has no box for. Example: {"seed": 7}. Leave empty normally. | |
| max_concurrentopt | INT | 11–32 | How many paid fal calls may run at the same time in one run, across every fal node. 1 (default) = one after another. This node starts its paid part only while fewer than this many fal calls are running. Once any fal node fails, the ones still waiting are not started, so nothing more is billed. |
Outputs (7)
| Name | Type | Description |
|---|---|---|
| images | IMAGE | — |
| image_paths | STRING | — |
| seed | INT | — |
| timings | STRING | — |
| prompt | STRING | — |
| has_nsfw_concepts | STRING | — |
| info | STRING | JSON: request id, cost estimate, saved files and fal's full answer. |