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Glossary · ComfyUI Basics

What Is a Node in ComfyUI?

By Earngenix Team ·

⚡ Quick Answer

A node is a rectangular block in ComfyUI that does one specific job — loading a model, encoding a prompt, running the sampler, saving an image. You connect nodes together with wires to build a complete workflow, called a node graph.

ComfyUI represents the entire image-generation process visually. Instead of hidden settings buried in menus, every step is its own node sitting on the canvas, and you can see exactly how data flows from one to the next by following the wires.

How Nodes Work

Each node has:

  • Inputs — connection points on the left side, where data flows in
  • Outputs — connection points on the right side, where data flows out
  • Widgets — dropdowns, sliders, and text boxes for settings specific to that node (like a checkpoint filename or a sampling method)

You connect an output on one node to a matching input on another by dragging a wire between them. ComfyUI only lets you connect compatible types — you can't accidentally wire an image output into a text input.

A Basic Node Chain, Explained

A simple text-to-image workflow chains together:

  1. Load Checkpoint — loads your model, outputs MODEL, CLIP, and VAE
  2. CLIP Text Encode (x2) — turns your positive and negative prompts into data the model understands
  3. Empty Latent Image — sets your output resolution
  4. KSampler — the node that actually generates the image, using the model, your encoded prompts, and the latent image size
  5. VAE Decode — converts the sampler's output into a viewable image
  6. Save Image — writes the final image to disk
Tip: See this full chain built step by step in our Text-to-Image workflow guide.

Frequently Asked Questions

Right-click anywhere on the empty canvas and select "Add Node," then browse or search the category list. You can also double-click the canvas and type a node name to search directly.

ComfyUI blocks connections between mismatched data types — for example, you can’t connect an IMAGE output directly into a MODEL input. Check that the output type on one side matches the input you’re trying to connect it to.

A node is a single step. A workflow is the full chain of connected nodes that together produce a result, from loading your model to saving the final image.

See It In Action

Ready to build your first node graph?

Our interface guide walks through the canvas, adding nodes, and wiring your first workflow.

Published: 2026-08-25 · Last updated: 2026-08-25

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