Blackforestlabs FLUX 3 Image API | Pricing & Docs

blackforestlabs/flux-3/text-to-image

FLUX 3 Image creates text-to-image pictures up to 4K. FLUX 3 Image Edit, in the same family, handles local edits and up to 10 references.

1. Get started

Use RunComfy's API to run blackforestlabs/flux-3/text-to-image. For accepted inputs and outputs, see the model's schema.

curl --request POST \
  --url https://model-api.runcomfy.net/v1/models/blackforestlabs/flux-3/text-to-image \
  --header "Content-Type: application/json" \
  --header "Authorization: Bearer <token>" \
  --data '{
    "prompt": ""
  }'

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-3/text-to-image \
  --header "Content-Type: application/json" \
  --header "Authorization: Bearer <token>" \
  --data '{
    "prompt": ""
  }'

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 schema",
  "required": [
    "prompt"
  ],
  "properties": {
    "prompt": {
      "title": "Prompt",
      "description": "Describe the subject, composition, lighting, style, and any text to include.",
      "type": "string",
      "examples": [
        "Studio product photograph of a sculptural chrome teapot with a cobalt-blue handle and a single crimson accent lid, one soft shadow on a warm cream sweep background, Bauhaus-inspired minimalism, bold primary colors, crisp commercial lighting, ultra-sharp detail."
      ]
    },
    "aspect_ratio": {
      "title": "Aspect Ratio",
      "description": "The aspect ratio of the generated image.",
      "type": "string",
      "enum": [
        "21:9",
        "2:1",
        "16:9",
        "3:2",
        "7:5",
        "4:3",
        "5:4",
        "1:1",
        "4:5",
        "3:4",
        "5:7",
        "2:3",
        "9:16",
        "1:2"
      ],
      "default": "1:1"
    },
    "resolution": {
      "title": "Resolution",
      "description": "Output resolution tier. Higher tiers cost more; 4K can take several minutes.",
      "type": "string",
      "enum": [
        "1k",
        "2k",
        "4k"
      ],
      "default": "1k"
    },
    "output_format": {
      "title": "Output Format",
      "description": "The format of the generated image.",
      "type": "string",
      "enum": [
        "jpeg",
        "png"
      ],
      "default": "jpeg"
    },
    "enable_prompt_expansion": {
      "title": "Enable Prompt Expansion",
      "description": "Expand the prompt while preserving its intent and the roles of reference images.",
      "type": "boolean",
      "default": false
    }
  }
}

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"
        }
      }
    }
  }
}

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.

1. Get started

Use RunComfy's API to run blackforestlabs/flux-3/text-to-image. For accepted inputs and outputs, see the model's schema.

curl --request POST \
  --url https://model-api.runcomfy.net/v1/models/blackforestlabs/flux-3/text-to-image \
  --header "Content-Type: application/json" \
  --header "Authorization: Bearer <token>" \
  --data '{
    "prompt": ""
  }'

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-3/text-to-image \
  --header "Content-Type: application/json" \
  --header "Authorization: Bearer <token>" \
  --data '{
    "prompt": ""
  }'

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)

5. Schema

Input schema

{
  "type": "object",
  "title": "Input schema",
  "required": [
    "prompt"
  ],
  "properties": {
    "prompt": {
      "title": "Prompt",
      "description": "Describe the subject, composition, lighting, style, and any text to include.",
      "type": "string",
      "examples": [
        "Studio product photograph of a sculptural chrome teapot with a cobalt-blue handle and a single crimson accent lid, one soft shadow on a warm cream sweep background, Bauhaus-inspired minimalism, bold primary colors, crisp commercial lighting, ultra-sharp detail."
      ]
    },
    "aspect_ratio": {
      "title": "Aspect Ratio",
      "description": "The aspect ratio of the generated image.",
      "type": "string",
      "enum": [
        "21:9",
        "2:1",
        "16:9",
        "3:2",
        "7:5",
        "4:3",
        "5:4",
        "1:1",
        "4:5",
        "3:4",
        "5:7",
        "2:3",
        "9:16",
        "1:2"
      ],
      "default": "1:1"
    },
    "resolution": {
      "title": "Resolution",
      "description": "Output resolution tier. Higher tiers cost more; 4K can take several minutes.",
      "type": "string",
      "enum": [
        "1k",
        "2k",
        "4k"
      ],
      "default": "1k"
    },
    "output_format": {
      "title": "Output Format",
      "description": "The format of the generated image.",
      "type": "string",
      "enum": [
        "jpeg",
        "png"
      ],
      "default": "jpeg"
    },
    "enable_prompt_expansion": {
      "title": "Enable Prompt Expansion",
      "description": "Expand the prompt while preserving its intent and the roles of reference images.",
      "type": "boolean",
      "default": false
    }
  }
}

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"
        }
      }
    }
  }
}

FLUX 3 Image creates text-to-image pictures up to 4K. FLUX 3 Image Edit, in the same family, handles local edits and up to 10 references.

Table of contents

1. Get started

2. Authentication

3. API reference

Submit a request

Monitor request status

Retrieve request results

Cancel a request

4. File inputs

Hosted file (URL)

5. Schema

Input schema

Output schema

FLUX 3 Image creates text-to-image pictures up to 4K. FLUX 3 Image Edit, in the same family, handles local edits and up to 10 references.

Table of contents

1. Get started

2. Authentication

3. API reference

Submit a request

Monitor request status

Retrieve request results

Cancel a request

4. File inputs

Hosted file (URL)

5. Schema

Input schema

Output schema

FLUX 3 Image: Text-to-Image and Image Edit on Models and API | RunComfy

FLUX 3 Image creates text-to-image pictures up to 4K. FLUX 3 Image Edit, in the same family, handles local edits and up to 10 references.

Table of contents

1. Get started

2. Authentication

3. API reference

Submit a request

Monitor request status

Retrieve request results

Cancel a request

4. File inputs

Hosted file (URL)

5. Schema

Input schema

Output schema

FLUX 3 Image: Text-to-Image and Image Edit on Models and API | RunComfy

FLUX 3 Image creates text-to-image pictures up to 4K. FLUX 3 Image Edit, in the same family, handles local edits and up to 10 references.

Table of contents

1. Get started

2. Authentication

3. API reference

Submit a request

Monitor request status

Retrieve request results

Cancel a request

4. File inputs

Hosted file (URL)

5. Schema

Input schema

Output schema