Utility Merge Video is a simple, reliable ComfyUI workflow for stitching clips end-to-end. It uses two or four LoadVideo nodes to decode your source files into frame batches, passes them into the Utility Merge Videos (Subgraph) node (ID: fbb76376-8768-4ece-9b41-a646f5e46ac3), and concatenates those frame sequences in order. The merged frames are then written to disk with SaveVideo.
Technically, the subgraph concatenates batches rather than compositing them, so the result plays one clip after another. A switch inside the Utility Merge Videos subgraph lets you choose between 2-input and 4-input modes. All inputs must share the same resolution; otherwise, the graph will error at merge time. The SaveVideo node controls the output file path, format (via extension), and playback FPS; the final FPS you set there determines how the concatenated frames will play back. A MarkdownNote node in the graph provides quick reminders right where you work.
API
Use this workflow from code
Every Comfy workflow is a JSON graph. The payload below is this workflow, exactly as ComfyUI runs it — fetch it from the URL, keep it in version control, or load it in ComfyUI and run it node by node.
GET https://comfy.org/workflows/download/81ba03930d2b.jsonFetching workflow JSON…
Run it from Python or TypeScript with the Comfy SDK. The same code targets Comfy Cloud or a ComfyUI you host yourself — only the base URL changes.
# Install (beta)
pip install comfy-sdk # Python
npm i @comfyorg/sdk # TypeScript
# Run this workflow (Python)
from comfy_sdk import Comfy
client = Comfy(api_key="comfyui-...")
wf = client.workflows.from_file("workflow_api.json")
job = client.run(wf)
for output in job.get_outputs("<output-node-id>"):
output.to_file(output.name)The SDK takes a workflow in API format: open this workflow in ComfyUI and use File → Export Workflow (API). API access requires a Comfy Cloud plan with an API key. SDK docs · Get an API key
FAQ
