Extensions/ComfyUI-NanoBanana_APIv3_node
ComfyUI Extension

ComfyUI-NanoBanana_APIv3_node

A ComfyUI custom node for Google Vertex AI / Gemini image generation with workflow-level parallel execution.

By darrell-goh·Created 7 months ago·Updated 7 months ago· 1
darrell-goh/ComfyUI-NanoBanana_APIv3_node
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ComfyUI Nano Banana Node V3

A ComfyUI custom node for Google Vertex AI / Gemini image generation with workflow-level parallel execution. Multiple instances of this node run concurrently within a workflow, enabling faster batch processing.

License: MIT ComfyUI

Note: This is the V3 (parallel execution) version designed for ComfyUI 0.3.x+. For the legacy version with chat mode and multi-output nodes, see ComfyUI-Nanobanana_node.

Features

  • Workflow-Level Parallel Execution - Multiple nodes run concurrently using ComfyUI's V3 async execution engine
  • Dynamic Image Inputs - 3 fixed image inputs always visible, with additional slots appearing dynamically as you connect images (up to 14 total)
  • Image Generation - Generate images with Gemini models through Vertex AI with customizable resolution (1K/2K/4K) and aspect ratios
  • Auto Aspect Ratio Detection - Automatically detects and matches aspect ratio from input images
  • Real-time Usage Metadata Display - Shows processing time and token counts directly on the node UI
  • Thoughts Output - Separate output for model reasoning/thinking content (for supported models)
  • Per-Instance Logging - Execution logs saved to logs/ directory in JSON Lines format

Requirements

  • ComfyUI 0.3.x or later (requires V3 node support via comfy_api.latest)
  • Python 3.10+
  • Valid Vertex AI API key or Nano Banana proxy endpoint

Python Dependencies

aiohttp>=3.8.0
Pillow
python-dotenv
numpy
torch

Installation

  1. Clone the repository into your ComfyUI custom_nodes/ folder:

    cd ComfyUI/custom_nodes
git clone https://github.com/darrell-goh/ComfyUI-NanoBanana_APIv3_node.git

  2. Install dependencies:

    pip install -r requirements.txt

  3. Configure environment variables:

    cp .env.template .env

    Edit .env with your API credentials (see Configuration below).

  4. Restart ComfyUI

Configuration

Create a .env file in the node folder with your API credentials:

Option 1: Nano Banana Proxy (Recommended)

VERTEX_AI_API_KEY=your_api_key_here
VERTEX_AI_USE_SIMPLE_ENDPOINT=true
VERTEX_AI_ENDPOINT=https://your-nano-banana-endpoint.com
VERTEX_AI_MODELS=gemini-3-pro-image-preview,gemini-2.5-flash-image

Option 2: Direct Vertex AI

VERTEX_AI_API_KEY=your_vertex_ai_api_key
VERTEX_AI_USE_SIMPLE_ENDPOINT=false
VERTEX_AI_PROJECT=your-gcp-project-id
VERTEX_AI_LOCATION=us-central1
VERTEX_AI_MODELS=gemini-3-pro-image-preview,gemini-2.5-flash-image

Node Reference

Nano Banana (Pro) V3

The main node for interacting with Gemini models through Vertex AI.

Inputs

| Input | Type | Description | |-------|------|-------------| | system_prompt | STRING | System prompt that sets the behavior of the model | | user_message_box | STRING | User message/prompt to send to the model | | model | COMBO | Gemini model to use (configured via VERTEX_AI_MODELS) | | image_generation | BOOLEAN | Enable image generation mode | | resolution | COMBO | Output resolution: 1K, 2K, or 4K | | aspect_ratio | COMBO | Aspect ratio: None, Auto, 1:1, 4:3, 3:4, 16:9, 9:16, 3:2, 2:3, 5:4, 4:5, 21:9 | | temperature | FLOAT | Controls randomness (0.0 - 1.0) | | timeout | INT | Request timeout in seconds (30-600, default: 300) | | image_1-3 | IMAGE | Fixed image inputs (always visible) | | image_4-14 | IMAGE | Dynamic image inputs (appear when fixed inputs are connected) |

Outputs

| Output | Type | Description | |--------|------|-------------| | Text Output | STRING | Text response from the model | | Image | IMAGE | Generated image tensor (if image generation enabled) | | Stats | STRING | Execution statistics (TPS, time, token count) | | Thoughts | STRING | Model's reasoning/thinking content (if available) |

On-Node Metadata Display

When execution completes, the node displays real-time statistics:

  • Aspect Ratio (green) - Auto-detected aspect ratio (e.g., "Auto → 16:9")
  • Processing Time (cyan) - Request duration in seconds
  • Output Tokens (yellow) - Number of output tokens generated
  • Thinking Tokens (magenta) - Reasoning tokens (for supported models)
  • Total Tokens (yellow) - Total token count

Parallel Execution

This node leverages ComfyUI's V3 async execution model. When multiple Nano Banana V3 nodes exist in a workflow without dependencies on each other, they execute concurrently rather than sequentially.

Example

A workflow with 4 independent image generation nodes will run all 4 API calls in parallel:

┌─────────────┐     ┌─────────────┐
│ Load Image  │────▶│ NanoBanana  │──┐
└─────────────┘     │    V3 #1    │  │
                    └─────────────┘  │
┌─────────────┐     ┌─────────────┐  │    ┌─────────────┐
│ Load Image  │────▶│ NanoBanana  │──┼───▶│   Output    │
└─────────────┘     │    V3 #2    │  │    │   Gallery   │
                    └─────────────┘  │    └─────────────┘
┌─────────────┐     ┌─────────────┐  │
│ Load Image  │────▶│ NanoBanana  │──┘
└─────────────┘     │    V3 #3    │
                    └─────────────┘

All three NanoBanana nodes execute their API requests simultaneously, significantly reducing total workflow time.

Logging

Execution logs are saved to the logs/ directory in JSON Lines format:

logs/
├── node_1.log    # Logs for node ID 1
├── node_2.log    # Logs for node ID 2
└── ...

Each log entry contains:

  • Timestamp
  • Workflow run ID
  • Node ID
  • Model used
  • Usage metadata (tokens, processing time)
  • Prompt and response previews

Troubleshooting

Node not appearing in ComfyUI

  • Ensure you're running ComfyUI 0.3.x or later (V3 node support required)
  • Check the ComfyUI console for import errors
  • Verify all dependencies are installed

API errors

  • Check that your .env file is properly configured
  • Verify your API key is valid
  • Ensure the endpoint URL is correct

Metadata not displaying on node

  • This feature requires ComfyUI's PromptServer (should be available by default)
  • Check browser console for JavaScript errors

Changelog

v1.0.0

  • Initial V3 release with parallel execution support
  • Real-time usage metadata display on node UI
  • Dynamic image inputs (up to 14 images)
  • Auto aspect ratio detection
  • Thoughts output for reasoning models
  • Per-instance JSON logging
  • Support for Gemini 3 Pro and Gemini 2.5 Flash models

License

MIT License - see LICENSE file.

Credits

  • Built for use with ComfyUI
  • Powered by Google Vertex AI API