Blackforestlabs Flux 2 LoRA API | Pricing & Docs

blackforestlabs/flux-2/lora

Generate highly customized images with the Black Forest Labs Flux 2 model by applying up to three LoRA adapters for precise style and character control on RunComfy.

1. Get started

Use RunComfy's API to run blackforestlabs/flux-2/lora. For accepted inputs and outputs, see the model's schema.

curl --request POST \
  --url https://model-api.runcomfy.net/v1/models/blackforestlabs/flux-2/lora \
  --header "Content-Type: application/json" \
  --header "Authorization: Bearer <token>" \
  --data '{
    "prompt": "GRPZA, dwarf warrior red beard, white background, game asset, pixel art"
  }'

2. Authentication

Set the YOUR_API_TOKEN environment variable with your API key (manage keys in your Profile) and include it on every request as a Bearer token via the Authorization header: Authorization: Bearer $YOUR_API_TOKEN.

3. API reference

Submit a request

Submit an asynchronous generation job and immediately receive a request_id plus URLs to check status, fetch results, and cancel.

curl --request POST \
  --url https://model-api.runcomfy.net/v1/models/blackforestlabs/flux-2/lora \
  --header "Content-Type: application/json" \
  --header "Authorization: Bearer <token>" \
  --data '{
    "prompt": "GRPZA, dwarf warrior red beard, white background, game asset, pixel art"
  }'

Monitor request status

Fetch the current state for a request_id ("in_queue", "in_progress", "completed", or "cancelled").

curl --request GET \
  --url https://model-api.runcomfy.net/v1/requests/{request_id}/status \
  --header "Authorization: Bearer <token>"

Retrieve request results

Retrieve the final outputs and metadata for the given request_id; if the job is not complete, the response returns the current state so you can continue polling.

curl --request GET \
  --url https://model-api.runcomfy.net/v1/requests/{request_id}/result \
  --header "Authorization: Bearer <token>"

Cancel a request

Cancel a queued job by request_id, in-progress jobs cannot be cancelled.

curl --request POST \
  --url https://model-api.runcomfy.net/v1/requests/{request_id}/cancel \
  --header "Authorization: Bearer <token>"

4. File inputs

Hosted file (URL)

Provide a publicly reachable HTTPS URL. Ensure the host allows server‑side fetches (no login/cookies required) and isn't rate‑limited or blocking bots. Recommended limits: images ≤ 50 MB (~4K), videos ≤ 100 MB (~2–5 min @ 720p). Prefer stable or pre‑signed URLs for private assets.

5. Schema

Input schema

{
  "type": "object",
  "title": "Input",
  "required": [
    "prompt"
  ],
  "properties": {
    "prompt": {
      "title": "Prompt",
      "description": "The prompt to generate an image from.",
      "type": "string",
      "default": "GRPZA, dwarf warrior red beard, white background, game asset, pixel art"
    },
    "guidance_scale": {
      "title": "Guidance Scale",
      "description": "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.",
      "type": "float",
      "minimum": 0,
      "maximum": 20,
      "default": 2.5
    },
    "seed": {
      "title": "Seed",
      "description": "The seed to use for the generation. If not provided, a random seed will be used.",
      "type": "integer",
      "default": 0
    },
    "num_inference_steps": {
      "title": "Number of Inference Steps",
      "description": "The number of inference steps to perform.",
      "type": "integer",
      "minimum": 4,
      "maximum": 50,
      "default": 28
    },
    "image_size": {
      "title": "Image Size",
      "description": "",
      "type": "string",
      "enum": [
        "square_hd",
        "square",
        "portrait_4_3",
        "portrait_16_9",
        "landscape_4_3",
        "landscape_16_9"
      ],
      "default": "landscape_4_3"
    },
    "output_format": {
      "title": "Output Format",
      "description": "The format of the generated image.",
      "type": "string",
      "enum": [
        "jpeg",
        "png",
        "webp"
      ],
      "default": "png"
    },
    "loras": {
      "title": "LoRAs",
      "description": "List of LoRA weights to apply (maximum 3). Each LoRA can be a URL, HuggingFace repo ID, or local path.",
      "type": "array",
      "default": [
        {
          "path": "gokaygokay/Flux-2D-Game-Assets-LoRA",
          "scale": 1
        }
      ],
      "items": {
        "path": {
          "title": "LoRA Path",
          "description": "URL, HuggingFace repo ID (owner/repo), or local path to LoRA weights.",
          "type": "string",
          "format": "str",
          "default": ""
        },
        "scale": {
          "title": "LoRA Scale",
          "description": "Scale factor for LoRA application (0.0 to 4.0). ",
          "type": "float",
          "format": "float_slider_with_range",
          "minimum": 0,
          "maximum": 4,
          "default": 1
        }
      },
      "maxItems": 3,
      "minItems": 0
    }
  }
}

Output schema

{
  "output": {
    "type": "object",
    "properties": {
      "image": {
        "type": "string",
        "format": "uri",
        "description": "single image URL"
      },
      "video": {
        "type": "string",
        "format": "uri",
        "description": "single video URL"
      },
      "images": {
        "type": "array",
        "description": "multiple image URLs",
        "items": { "type": "string", "format": "uri" }
      },
      "videos": {
        "type": "array",
        "description": "multiple video URLs",
        "items": { "type": "string", "format": "uri" }
      }
    }
  }
}

Support

Video Models/Tools

Image Models

Legal

RunComfy

RunComfy is the premier ComfyUI platform, offering ComfyUI online environment and services, along with ComfyUI workflows featuring stunning visuals. RunComfy also provides AI Models, enabling artists to harness the latest AI tools to create incredible art.

Flux 2 LoRA: Text-to-Image with Custom LoRA & Precise Control on playground and API | RunComfy