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The Instance Proxy API lets you call ComfyUI’s native backend endpoints on a live instance. After you submit a job via the async queue, the status response will include an instance_id once the instance is active. With that ID, you can send authenticated requests through a proxy path to perform operational tasks such as unloading models or freeing GPU memory.

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When to use the proxy

Start proxy calls once the request status is in_progress (after cold start) or completed, and you can read instance_id from the Status endpoint:

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Instance proxy endpoint

Base URL: https://api.runcomfy.net

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Path parameters

  • deployment_id: string (required)
  • instance_id: string (required)
  • comfy_backend_path: string (required) — the target ComfyUI backend route, e.g. api/free

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What you can call

The proxy forwards your request to the live instance. Common targets include:
  • ComfyUI backend endpoints (e.g. GET /object_info, POST /api/prompt)
  • ComfyUI Manager endpoints (e.g. POST /api/free)

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Free memory / unload models

You can release GPU memory or unload models via ComfyUI Manager’s native POST /api/free endpoint. This can be useful in long-running sessions to ensure the next request starts from a clean state.

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Request example: unload models only

Meaning in ComfyUI: Unloads currently loaded model weights (checkpoints/LoRAs/CLIP/VAE) from memory; does not clear the execution cache.
Equivalent in the ComfyUI web UI: Manager → Unload models. Unload models in ComfyUI

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Request example: unload models and free memory

Meaning in ComfyUI: Unloads models and clears the execution cache to return cached GPU VRAM.
Equivalent in the ComfyUI web UI: Manager → Unload models and Clear execution cache (free memory). Unload models + clear execution cache in ComfyUI

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Response example

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Lifecycle notes and errors

  • An instance_id is valid only while its instance is running. If the instance shuts down due to keep-warm/idle timeout, subsequent proxy calls will fail. Submit a new job to start a fresh instance and obtain a new instance_id.
  • Immediately after submitting a request, proxy calls may fail until the job status shows in_progress (after cold start) or completed in the status endpoint. Poll status and retry once it transitions.