Blackforestlabs FLUX 3 Keyframes to Video API | Pricing & Docs

blackforestlabs/flux-3/keyframes-to-video

FLUX 3 Keyframes to Video builds a clip from prompt-guided motion between stills locked to exact frame positions, with optional native audio at 720p or 1080p.

1. Get started

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

curl --request POST \
  --url https://model-api.runcomfy.net/v1/models/blackforestlabs/flux-3/keyframes-to-video \
  --header "Content-Type: application/json" \
  --header "Authorization: Bearer <token>" \
  --data '{
    "prompt": "One continuous tracking shot: she starts on the wet coastal road facing the distant lighthouse, walks through the wooden gate as the mist thins, and arrives at the lighthouse base just as sunlight breaks through. Soft ocean spray, distant gulls, natural footsteps on wet asphalt.",
    "keyframes": [
      {
        "image_url": "https://playgrounds-storage-public.runcomfy.net/tools/7399/media-files/ref-promo-1.webp",
        "frame_index": 0
      },
      {
        "image_url": "https://playgrounds-storage-public.runcomfy.net/tools/7399/media-files/ref-promo-2.webp",
        "frame_index": 60
      },
      {
        "image_url": "https://playgrounds-storage-public.runcomfy.net/tools/7399/media-files/ref-promo-3.webp",
        "frame_index": 120
      }
    ]
  }'

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/keyframes-to-video \
  --header "Content-Type: application/json" \
  --header "Authorization: Bearer <token>" \
  --data '{
    "prompt": "One continuous tracking shot: she starts on the wet coastal road facing the distant lighthouse, walks through the wooden gate as the mist thins, and arrives at the lighthouse base just as sunlight breaks through. Soft ocean spray, distant gulls, natural footsteps on wet asphalt.",
    "keyframes": [
      {
        "image_url": "https://playgrounds-storage-public.runcomfy.net/tools/7399/media-files/ref-promo-1.webp",
        "frame_index": 0
      },
      {
        "image_url": "https://playgrounds-storage-public.runcomfy.net/tools/7399/media-files/ref-promo-2.webp",
        "frame_index": 60
      },
      {
        "image_url": "https://playgrounds-storage-public.runcomfy.net/tools/7399/media-files/ref-promo-3.webp",
        "frame_index": 120
      }
    ]
  }'

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",
    "keyframes"
  ],
  "properties": {
    "prompt": {
      "title": "Prompt",
      "description": "The text prompt describing the video you want to generate.",
      "type": "string",
      "default": "One continuous tracking shot: she starts on the wet coastal road facing the distant lighthouse, walks through the wooden gate as the mist thins, and arrives at the lighthouse base just as sunlight breaks through. Soft ocean spray, distant gulls, natural footsteps on wet asphalt."
    },
    "keyframes": {
      "title": "Keyframes",
      "description": "Keyframe images pinned to frame positions in the generated video. Up to 10 keyframes with unique frame_index values (0-based, at most duration × 24 at 24 fps).",
      "type": "array",
      "default": [
        {
          "image_url": "https://playgrounds-storage-public.runcomfy.net/tools/7399/media-files/ref-promo-1.webp",
          "frame_index": 0
        },
        {
          "image_url": "https://playgrounds-storage-public.runcomfy.net/tools/7399/media-files/ref-promo-2.webp",
          "frame_index": 60
        },
        {
          "image_url": "https://playgrounds-storage-public.runcomfy.net/tools/7399/media-files/ref-promo-3.webp",
          "frame_index": 120
        }
      ],
      "items": {
        "image_url": {
          "title": "Image URL",
          "description": "URL of the keyframe image (PNG, JPEG, or WebP).",
          "type": "string",
          "format": "image_uri",
          "default": ""
        },
        "frame_index": {
          "title": "Frame Index",
          "description": "Frame position of this keyframe in the generated 24 fps video. Must be unique and at most duration × 24.",
          "type": "integer",
          "format": "int_slider_with_range",
          "minimum": 0,
          "maximum": 480,
          "default": 0
        }
      },
      "maxItems": 10,
      "minItems": 1
    },
    "aspect_ratio": {
      "title": "Aspect Ratio",
      "description": "Aspect ratio of the generated video. auto lets the model choose.",
      "type": "string",
      "enum": [
        "auto",
        "21:9",
        "2:1",
        "16:9",
        "4:3",
        "1:1",
        "3:4",
        "9:16"
      ],
      "default": "16:9"
    },
    "resolution": {
      "title": "Resolution",
      "description": "Resolution of the generated video.",
      "type": "string",
      "enum": [
        "720p",
        "1080p"
      ],
      "default": "720p"
    },
    "duration": {
      "title": "Duration",
      "description": "Duration of the generated video in seconds. An explicit duration is required to validate keyframe positions.",
      "type": "integer",
      "enum": [
        5,
        6,
        7,
        8,
        9,
        10,
        11,
        12,
        13,
        14,
        15,
        16,
        17,
        18,
        19,
        20
      ],
      "default": 5
    },
    "generate_audio": {
      "title": "Generate Audio",
      "description": "Whether to generate audio for the video.",
      "type": "boolean",
      "default": true
    },
    "safety_tolerance": {
      "title": "Safety Tolerance",
      "description": "The safety tolerance level for the generated video. 0 is the strictest and 4 is the most permissive.",
      "type": "integer",
      "minimum": 0,
      "maximum": 4,
      "default": 2
    }
  }
}

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/keyframes-to-video. For accepted inputs and outputs, see the model's schema.

curl --request POST \
  --url https://model-api.runcomfy.net/v1/models/blackforestlabs/flux-3/keyframes-to-video \
  --header "Content-Type: application/json" \
  --header "Authorization: Bearer <token>" \
  --data '{
    "prompt": "One continuous tracking shot: she starts on the wet coastal road facing the distant lighthouse, walks through the wooden gate as the mist thins, and arrives at the lighthouse base just as sunlight breaks through. Soft ocean spray, distant gulls, natural footsteps on wet asphalt.",
    "keyframes": [
      {
        "image_url": "https://playgrounds-storage-public.runcomfy.net/tools/7399/media-files/ref-promo-1.webp",
        "frame_index": 0
      },
      {
        "image_url": "https://playgrounds-storage-public.runcomfy.net/tools/7399/media-files/ref-promo-2.webp",
        "frame_index": 60
      },
      {
        "image_url": "https://playgrounds-storage-public.runcomfy.net/tools/7399/media-files/ref-promo-3.webp",
        "frame_index": 120
      }
    ]
  }'

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/keyframes-to-video \
  --header "Content-Type: application/json" \
  --header "Authorization: Bearer <token>" \
  --data '{
    "prompt": "One continuous tracking shot: she starts on the wet coastal road facing the distant lighthouse, walks through the wooden gate as the mist thins, and arrives at the lighthouse base just as sunlight breaks through. Soft ocean spray, distant gulls, natural footsteps on wet asphalt.",
    "keyframes": [
      {
        "image_url": "https://playgrounds-storage-public.runcomfy.net/tools/7399/media-files/ref-promo-1.webp",
        "frame_index": 0
      },
      {
        "image_url": "https://playgrounds-storage-public.runcomfy.net/tools/7399/media-files/ref-promo-2.webp",
        "frame_index": 60
      },
      {
        "image_url": "https://playgrounds-storage-public.runcomfy.net/tools/7399/media-files/ref-promo-3.webp",
        "frame_index": 120
      }
    ]
  }'

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",
    "keyframes"
  ],
  "properties": {
    "prompt": {
      "title": "Prompt",
      "description": "The text prompt describing the video you want to generate.",
      "type": "string",
      "default": "One continuous tracking shot: she starts on the wet coastal road facing the distant lighthouse, walks through the wooden gate as the mist thins, and arrives at the lighthouse base just as sunlight breaks through. Soft ocean spray, distant gulls, natural footsteps on wet asphalt."
    },
    "keyframes": {
      "title": "Keyframes",
      "description": "Keyframe images pinned to frame positions in the generated video. Up to 10 keyframes with unique frame_index values (0-based, at most duration × 24 at 24 fps).",
      "type": "array",
      "default": [
        {
          "image_url": "https://playgrounds-storage-public.runcomfy.net/tools/7399/media-files/ref-promo-1.webp",
          "frame_index": 0
        },
        {
          "image_url": "https://playgrounds-storage-public.runcomfy.net/tools/7399/media-files/ref-promo-2.webp",
          "frame_index": 60
        },
        {
          "image_url": "https://playgrounds-storage-public.runcomfy.net/tools/7399/media-files/ref-promo-3.webp",
          "frame_index": 120
        }
      ],
      "items": {
        "image_url": {
          "title": "Image URL",
          "description": "URL of the keyframe image (PNG, JPEG, or WebP).",
          "type": "string",
          "format": "image_uri",
          "default": ""
        },
        "frame_index": {
          "title": "Frame Index",
          "description": "Frame position of this keyframe in the generated 24 fps video. Must be unique and at most duration × 24.",
          "type": "integer",
          "format": "int_slider_with_range",
          "minimum": 0,
          "maximum": 480,
          "default": 0
        }
      },
      "maxItems": 10,
      "minItems": 1
    },
    "aspect_ratio": {
      "title": "Aspect Ratio",
      "description": "Aspect ratio of the generated video. auto lets the model choose.",
      "type": "string",
      "enum": [
        "auto",
        "21:9",
        "2:1",
        "16:9",
        "4:3",
        "1:1",
        "3:4",
        "9:16"
      ],
      "default": "16:9"
    },
    "resolution": {
      "title": "Resolution",
      "description": "Resolution of the generated video.",
      "type": "string",
      "enum": [
        "720p",
        "1080p"
      ],
      "default": "720p"
    },
    "duration": {
      "title": "Duration",
      "description": "Duration of the generated video in seconds. An explicit duration is required to validate keyframe positions.",
      "type": "integer",
      "enum": [
        5,
        6,
        7,
        8,
        9,
        10,
        11,
        12,
        13,
        14,
        15,
        16,
        17,
        18,
        19,
        20
      ],
      "default": 5
    },
    "generate_audio": {
      "title": "Generate Audio",
      "description": "Whether to generate audio for the video.",
      "type": "boolean",
      "default": true
    },
    "safety_tolerance": {
      "title": "Safety Tolerance",
      "description": "The safety tolerance level for the generated video. 0 is the strictest and 4 is the most permissive.",
      "type": "integer",
      "minimum": 0,
      "maximum": 4,
      "default": 2
    }
  }
}

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 Keyframes to Video builds a clip from prompt-guided motion between stills locked to exact frame positions, with optional native audio at 720p or 1080p.

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 Keyframes to Video builds a clip from prompt-guided motion between stills locked to exact frame positions, with optional native audio at 720p or 1080p.

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 Keyframes to Video: Multi-Keyframe Image to Video on Models and API | RunComfy

FLUX 3 Keyframes to Video builds a clip from prompt-guided motion between stills locked to exact frame positions, with optional native audio at 720p or 1080p.

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 Keyframes to Video: Multi-Keyframe Image to Video on Models and API | RunComfy

FLUX 3 Keyframes to Video builds a clip from prompt-guided motion between stills locked to exact frame positions, with optional native audio at 720p or 1080p.

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