ComfyUI Data Types

ComfyUI uses specific data types for node inputs and outputs. Understanding tensor shapes and data formats is essential.

Complete Type Reference

Tensor/Data Types

Model Types (opaque, typically pass-through)

3D Types

Widget Types (create UI controls)

Special Types

IMAGE Type

Images are torch.Tensor with shape [B, H, W, C]:

• B = batch size (1 for single image)
• H = height in pixels
• W = width in pixels
• C = channels (3 for RGB, values 0.0-1.0)

import torch
import numpy as np
from PIL import Image as PILImage

class ImageProcessor(io.ComfyNode):
    @classmethod
    def define_schema(cls):
        return io.Schema(
            node_id="ImageProcessor",
            display_name="Image Processor",
            category="image",
            inputs=[io.Image.Input("image")],
            outputs=[io.Image.Output("IMAGE")],
        )

    @classmethod
    def execute(cls, image):
        b, h, w, c = image.shape
        result = torch.clamp(image * 1.5, 0.0, 1.0)
        return io.NodeOutput(result)

Loading / Saving Images

from PIL import ImageOps

# Load from file → tensor
def load_image(path):
    img = PILImage.open(path)
    img = ImageOps.exif_transpose(img)   # fix rotation from camera EXIF
    if img.mode == "I":                  # handle 16-bit images
        img = img.point(lambda i: i * (1 / 255))
    img = img.convert("RGB")
    return torch.from_numpy(np.array(img).astype(np.float32) / 255.0).unsqueeze(0)

# Tensor → save to file
def save_image(tensor, path):
    if tensor.dim() == 4:
        tensor = tensor[0]
    PILImage.fromarray(np.clip(255.0 * tensor.cpu().numpy(), 0, 255).astype(np.uint8)).save(path)

# Batch operations
batch = torch.cat([img1, img2], dim=0)    # stack into batch
single = image[i]                          # extract from batch [H,W,C]
single_batch = image.unsqueeze(0)          # add batch dim [1,H,W,C]

MASK Type

torch.Tensor with shape [H, W] or [B, H, W], values 0.0-1.0.

# Invert mask
inverted = 1.0 - mask

# Mask ↔ Image conversion
alpha = mask.unsqueeze(0).unsqueeze(-1)                   # [1,H,W,1]
gray_mask = 0.299*img[:,:,:,0] + 0.587*img[:,:,:,1] + 0.114*img[:,:,:,2]
image_from_mask = mask.unsqueeze(-1).repeat(1, 1, 1, 3)  # [B,H,W,3]

# Ensure batch dim
if mask.dim() == 2:
    mask = mask.unsqueeze(0)  # [1, H, W]

LATENT Type

Dict with typed keys:

class LatentDict(TypedDict):
    samples: torch.Tensor       # [B, C, H, W] - required
    noise_mask: NotRequired[torch.Tensor]
    batch_index: NotRequired[list[int]]
    type: NotRequired[str]      # only for "audio", "hunyuan3dv2"

Latent dimensions are 1/8 of pixel dims. SD1.5/SDXL = 4 channels, SD3/Flux = 16 channels.

samples = latent["samples"]       # [B, C, H, W]
# Always preserve extra keys when modifying:
result = latent.copy()
result["samples"] = modified_samples

CONDITIONING Type

list[tuple[Tensor, PooledDict]] — a list of (cond_tensor, metadata_dict) pairs.

The PooledDict contains many optional keys for different models:

class PooledDict(TypedDict):
    pooled_output: torch.Tensor
    control: NotRequired[ControlNet]
    area: NotRequired[tuple[int, ...]]
    strength: NotRequired[float]           # default 1.0
    mask: NotRequired[torch.Tensor]
    start_percent: NotRequired[float]      # 0.0-1.0
    end_percent: NotRequired[float]        # 0.0-1.0
    guidance: NotRequired[float]           # Flux-like models
    hooks: NotRequired[HookGroup]
    # ... many more model-specific keys (SDXL, SVD, WAN, etc.)

Combine conditioning: result = cond_a + cond_b (list concatenation).

VIDEO Type

VideoInput is an abstract base class with methods:

class VideoInput(ABC):
    def get_components(self) -> VideoComponents    # images tensor + audio + frame_rate
    def save_to(self, path, format, codec, metadata)
    def as_trimmed(self, start_time, duration) -> VideoInput | None
    def get_stream_source(self) -> str | BytesIO
    def get_dimensions(self) -> tuple[int, int]     # (width, height)
    def get_duration(self) -> float                  # seconds
    def get_frame_count(self) -> int
    def get_frame_rate(self) -> Fraction
    def get_container_format(self) -> str

Concrete implementations: VideoFromFile, VideoFromComponents (available via from comfy_api.latest import InputImpl).

3D Types

File3D

from comfy_api.latest import Types

# File3D wraps a 3D file (disk path or BytesIO stream)
file_3d = Types.File3D(source="/path/to/model.glb", file_format="glb")
file_3d.format              # "glb"
file_3d.is_disk_backed      # True
file_3d.get_data()          # BytesIO
file_3d.get_bytes()         # raw bytes
file_3d.save_to("/output/model.glb")

MESH and VOXEL

from comfy_api.latest import Types

mesh = Types.MESH(vertices=torch.tensor(...), faces=torch.tensor(...))
voxel = Types.VOXEL(data=torch.tensor(...))

Widget Types with Special Features

Color

io.Color.Input("color", default="#ff0000", socketless=True)
# Value is a hex string like "#ff0000"

BoundingBox

io.BoundingBox.Input("bbox",
    default={"x": 0, "y": 0, "width": 512, "height": 512},
    socketless=True,
    component="my_component",  # optional custom UI component
)
# Value is {"x": int, "y": int, "width": int, "height": int}

Curve

io.Curve.Input("curve",
    default=[(0.0, 0.0), (1.0, 1.0)],  # linear
    socketless=True,
)
# Value is list of (x, y) tuples

MultiCombo

io.MultiCombo.Input("tags",
    options=["tag1", "tag2", "tag3"],
    default=["tag1"],
    placeholder="Select tags...",
    chip=True,  # show as chips
)
# Value is list[str]

Webcam

io.Webcam.Input("webcam_capture")
# Value is str (captured image data)

ImageCompare

io.ImageCompare.Input("comparison", socketless=True)
# Value is dict

Custom Types

# Simple: create inline custom type
MyData = io.Custom("MY_DATA_TYPE")

# Use in inputs/outputs
io.Schema(
    inputs=[MyData.Input("data")],
    outputs=[MyData.Output("MY_DATA")],
)

Advanced: @comfytype decorator

For custom types with type hints or custom Input/Output classes:

from comfy_api.latest._io import comfytype, ComfyTypeIO

@comfytype(io_type="MY_DATA_TYPE")
class MyData(ComfyTypeIO):
    Type = dict[str, Any]  # type hint for the data

AnyType / Wildcard

# Accept any single type (always a connection input, no widget)
io.AnyType.Input("anything")

# Accept specific multiple types
io.MultiType.Input("data", types=[io.Image, io.Mask, io.Latent])

# MultiType with widget override (shows widget for first type)
io.MultiType.Input(
    io.Float.Input("value", default=1.0),
    types=[io.Float, io.Int],
)

Imports from comfy_api.latest

from comfy_api.latest import (
    ComfyExtension,  # extension registration
    ComfyAPI,        # runtime API (progress, node replacement)
    io,              # all io types (io.Image, io.Schema, io.ComfyNode, etc.)
    ui,              # UI output helpers (ui.PreviewImage, ui.SavedImages, etc.)
    Input,           # Input.Image (ImageInput), Input.Audio, Input.Mask, Input.Latent, Input.Video
    InputImpl,       # InputImpl.VideoFromFile, InputImpl.VideoFromComponents
    Types,           # Types.MESH, Types.VOXEL, Types.File3D, Types.VideoCodec, etc.
)

Tensor Safety

When checking if a tensor exists, always use is not None instead of truthiness:

# CORRECT
if image is not None:
    process(image)

# WRONG — multi-element tensors don't support bool()
if image:       # raises RuntimeError
    process(image)

# For boolean conditions on tensors, use .all() or .any()
if (mask > 0.5).all():
    ...

Type Conversion Patterns

# IMAGE [B,H,W,C] → MASK [B,H,W]
mask = 0.299 * image[:,:,:,0] + 0.587 * image[:,:,:,1] + 0.114 * image[:,:,:,2]

# MASK [B,H,W] → IMAGE [B,H,W,C]
image = mask.unsqueeze(-1).repeat(1, 1, 1, 3)

# Resize image tensor
import torch.nn.functional as F
resized = F.interpolate(
    image.permute(0, 3, 1, 2),  # [B,C,H,W] for interpolate
    size=(new_h, new_w), mode='bilinear', align_corners=False
).permute(0, 2, 3, 1)  # back to [B,H,W,C]

See Also

• comfyui-node-basics - Node class structure and registration
• comfyui-node-inputs - Input configuration details (widget options)
• comfyui-node-outputs - Output types and UI outputs
• comfyui-node-advanced - MatchType, MultiType, Autogrow, DynamicCombo