ComfyUI accepts command-line arguments when started with python main.py. This page documents every flag defined in comfy/cli_args.py.
Windows Portable users can add flags to the .bat launch files (for example, run_nvidia_gpu.bat). See the Windows Portable guide for details. python main.py --help in your ComfyUI directory for the built-in help text. Combine multiple flags as needed:
python main.py --listen 0.0.0.0 --port 8288 --disable-auto-launch --lowvram
Network & Server
| Flag | Default | Description |
|---|
--listen [IP] | 127.0.0.1 | IP address to listen on. Comma-separated list supported (e.g. 127.2.2.2,127.3.3.3). If provided without a value, defaults to 0.0.0.0,:: (all IPv4 and IPv6 interfaces). |
--port | 8188 | Port to listen on. |
--tls-keyfile PATH | — | Path to TLS (SSL) key file. Enables HTTPS. Requires --tls-certfile. |
--tls-certfile PATH | — | Path to TLS (SSL) certificate file. Enables HTTPS. Requires --tls-keyfile. |
--enable-cors-header [ORIGIN] | disabled | Enable CORS. Optional origin, or * for all origins when no value is given. |
--max-upload-size | 100 | Maximum upload size in MB. |
--enable-compress-response-body | disabled | Enable compressing the HTTP response body. |
# Listen on all interfaces (LAN access)
python main.py --listen
# Listen on a specific IP
python main.py --listen 0.0.0.0
# Custom port with HTTPS
python main.py --port 8443 --tls-keyfile key.pem --tls-certfile cert.pem
Directories
| Flag | Default | Description |
|---|
--base-directory PATH | ComfyUI root | Base directory for models, custom_nodes, input, output, temp, and user directories. |
--extra-model-paths-config PATH | — | Load one or more extra_model_paths.yaml files. Can be specified multiple times. |
--output-directory PATH | — | Output directory. Overrides --base-directory. |
--temp-directory PATH | — | Temp directory. Overrides --base-directory. |
--input-directory PATH | — | Input directory. Overrides --base-directory. |
--user-directory PATH | — | User directory (absolute path). Overrides --base-directory. Path must exist and be readable. |
Launch & Browser
| Flag | Default | Description |
|---|
--auto-launch | disabled | Automatically open ComfyUI in the default browser on startup. |
--disable-auto-launch | disabled | Disable auto-launching the browser. |
--windows-standalone-build | disabled | Windows portable build convenience mode. Enables auto-launch on startup (equivalent to --auto-launch). |
--windows-standalone-build sets auto_launch to true. --disable-auto-launch overrides it. To run as a server without opening a browser, use --disable-auto-launch.
# Run server without opening browser
python main.py --disable-auto-launch
Devices & CUDA
| Flag | Default | Description |
|---|
--cuda-device DEVICE_ID | — | CUDA device IDs to use, comma-separated (e.g. 0 or 0,1). Other devices are hidden. |
--default-device ID | — | Default device ID. All other devices remain visible. |
--cuda-malloc | auto (torch 2.0+) | Enable cudaMallocAsync. Mutually exclusive with --disable-cuda-malloc. |
--disable-cuda-malloc | — | Disable cudaMallocAsync. Mutually exclusive with --cuda-malloc. |
--directml [DEVICE] | — | Use torch-directml. Optional device index; defaults to -1 when no value is given. |
--oneapi-device-selector STRING | — | oneAPI device selector string for Intel devices. |
Precision & Inference
Flags in the Global, UNET, VAE, and Text Encoder groups below are mutually exclusive within each group. Only one flag per group can be used at a time.
Global floating point
| Flag | Description |
|---|
--force-fp32 | Force fp32 globally. Report if this improves GPU performance. |
--force-fp16 | Force fp16 globally. Also sets --fp16-unet. |
UNET precision
| Flag | Description |
|---|
--fp32-unet | Run the diffusion model in fp32. |
--fp64-unet | Run the diffusion model in fp64. |
--bf16-unet | Run the diffusion model in bf16. |
--fp16-unet | Run the diffusion model in fp16. |
--fp8_e4m3fn-unet | Store UNet weights in fp8 (e4m3fn). |
--fp8_e5m2-unet | Store UNet weights in fp8 (e5m2). |
--fp8_e8m0fnu-unet | Store UNet weights in fp8 (e8m0fnu). |
VAE precision
| Flag | Description |
|---|
--fp16-vae | Run the VAE in fp16. May cause black images. |
--fp32-vae | Run the VAE in full precision fp32. |
--bf16-vae | Run the VAE in bf16. |
--cpu-vae | Run the VAE on the CPU (not mutually exclusive with VAE precision flags). |
Text encoder precision
| Flag | Description |
|---|
--fp8_e4m3fn-text-enc | Store text encoder weights in fp8 (e4m3fn). |
--fp8_e5m2-text-enc | Store text encoder weights in fp8 (e5m2). |
--fp16-text-enc | Store text encoder weights in fp16. |
--fp32-text-enc | Store text encoder weights in fp32. |
--bf16-text-enc | Store text encoder weights in bf16. |
Other inference options
| Flag | Default | Description |
|---|
--fp16-intermediates | disabled | Experimental: use fp16 for intermediate tensors between nodes instead of fp32. |
--force-channels-last | disabled | Force channels-last memory format during inference. |
--supports-fp8-compute | disabled | Act as if the device supports fp8 compute. |
--enable-triton-backend | disabled | Enable Triton backend in comfy-kitchen. Disabled by default at launch. |
Preview
| Flag | Default | Description |
|---|
--preview-method | none | Preview method for sampler nodes. Choices: none, auto, latent2rgb, taesd. |
--preview-size | 512 | Maximum preview image size in pixels. |
Cache
Cache mode flags are mutually exclusive. Only one of --cache-ram, --cache-classic, --cache-lru, or --cache-none should be used.
| Flag | Default | Description |
|---|
--cache-ram [GB] [GB] | enabled (default mode) | RAM pressure caching. First value: active-cache threshold in GB. Optional second value: inactive-cache/pin threshold in GB. When no values given: active = 10% of system RAM (min 2 GB, max 10 GB); inactive = 100% of system RAM (max 96 GB). Accepts at most two values. |
--cache-classic | — | Use the old aggressive caching style. |
--cache-lru N | 0 (disabled) | LRU caching with a maximum of N node results cached. May use more RAM/VRAM. |
--cache-none | — | Reduced RAM/VRAM usage; re-executes every node on each run. |
Attention
Cross-attention method flags are mutually exclusive. Split and quad attention are ignored when xformers is used.
| Flag | Description |
|---|
--use-split-cross-attention | Use split cross attention optimization. |
--use-quad-cross-attention | Use sub-quadratic cross attention optimization. |
--use-pytorch-cross-attention | Use PyTorch 2.0 cross attention. |
--use-sage-attention | Use Sage attention. |
--use-flash-attention | Use FlashAttention. |
--disable-xformers | Disable xformers. |
--force-upcast-attention | Force attention upcasting. Report if this fixes black images. Mutually exclusive with --dont-upcast-attention. |
--dont-upcast-attention | Disable all attention upcasting. For debugging only. |
VRAM & Memory
VRAM mode flags (--gpu-only, --highvram, --lowvram, --novram, --cpu) are mutually exclusive.
| Flag | Default | Description |
|---|
--gpu-only | — | Store and run everything on the GPU (text encoders, CLIP, etc.). |
--highvram | — | Keep models in GPU memory instead of unloading to CPU after use. |
--lowvram | — | No effect when dynamic VRAM is enabled. Otherwise, runs text encoders on CPU. |
--novram | — | Minimal VRAM usage when --lowvram is not enough. |
--cpu | — | Use CPU for everything (slow). |
--reserve-vram GB | OS-dependent | VRAM in GB to reserve for the OS and other software. |
--async-offload [NUM_STREAMS] | enabled on Nvidia | Async weight offloading. Optional stream count (default: 2). |
--disable-async-offload | — | Disable async weight offloading. |
--disable-dynamic-vram | — | Disable dynamic VRAM; use estimate-based model loading. |
--enable-dynamic-vram | auto on Nvidia | Enable dynamic VRAM on systems where it is not enabled by default. |
--fast-disk | disabled | Prefer disk-backed dynamic loading over unpinned RAM. Useful with fast NVMe. |
--force-non-blocking | disabled | Force non-blocking tensor operations. May help on non-Nvidia systems; can break some workflows. |
--disable-smart-memory | disabled | Aggressively offload to RAM instead of keeping models in VRAM. |
--disable-pinned-memory | disabled | Disable pinned memory use. |
--mmap-torch-files | disabled | Use mmap when loading ckpt/pt files. |
--disable-mmap | disabled | Do not use mmap when loading safetensors. |
| Flag | Default | Description |
|---|
--fast [OPT...] | disabled | Enable experimental optimizations that may affect quality or stability. --fast alone enables all. Specific options: fp16_accumulation, fp8_matrix_mult, cublas_ops, autotune. |
--deterministic | disabled | Use slower deterministic PyTorch algorithms where possible. Does not guarantee identical images in all cases. |
--default-hashing-function | sha256 | Hash function for duplicate filename/content comparison. Choices: md5, sha1, sha256, sha512. |
# Enable all fast optimizations (experimental)
python main.py --fast
# Enable specific optimizations only
python main.py --fast fp16_accumulation cublas_ops
ComfyUI Manager
See ComfyUI-Manager Installation for setup instructions.
| Flag | Description |
|---|
--enable-manager | Enable ComfyUI-Manager. |
--disable-manager-ui | Disable Manager UI and endpoints only. Background tasks (scheduled installs, etc.) continue. Requires --enable-manager. |
--enable-manager-legacy-ui | Use the legacy Manager UI. Requires --enable-manager. |
Custom Nodes & API Nodes
| Flag | Default | Description |
|---|
--disable-all-custom-nodes | disabled | Disable loading all custom nodes. |
--whitelist-custom-nodes FOLDER... | — | Custom node folders to load even when --disable-all-custom-nodes is set. |
--disable-api-nodes | disabled | Disable API nodes and prevent the frontend from communicating with the internet. |
--disable-metadata | disabled | Disable saving prompt metadata in output files. |
# Troubleshoot custom node issues
python main.py --disable-all-custom-nodes
# Allow only specific custom nodes
python main.py --disable-all-custom-nodes --whitelist-custom-nodes ComfyUI-Manager
Frontend & API
| Flag | Default | Description |
|---|
--front-end-version | comfyanonymous/ComfyUI@latest | Frontend version in [owner]/[repo]@[version] format. Requires internet to download from GitHub releases. Version can be latest or a semver (e.g. 1.0.0). |
--front-end-root PATH | — | Local filesystem path to the frontend directory. Overrides --front-end-version. |
--comfy-api-base | https://api.comfy.org | Base URL for the ComfyUI API. |
--database-url | sqlite:///<ComfyUI>/user/comfyui.db | Database URL. Use sqlite:///:memory: for in-memory. |
--enable-assets | disabled | Enable the assets system (API routes, database sync, background scanning). |
--feature-flag KEY[=VALUE] | — | Set a server feature flag. Bare KEY sets true. Can be repeated. Booleans and numbers are auto-converted. |
--list-feature-flags | — | Print known CLI-settable feature flags as JSON and exit. |
# List available feature flags
python main.py --list-feature-flags
# Set feature flags
python main.py --feature-flag show_signin_button=true
Logging & Misc
| Flag | Default | Description |
|---|
--verbose [LEVEL] | INFO | Logging level. Choices: DEBUG, INFO, WARNING, ERROR, CRITICAL. --verbose alone sets DEBUG. |
--log-stdout | disabled | Send normal process output to stdout instead of stderr. |
--dont-print-server | disabled | Do not print server output to the console. |
--multi-user | disabled | Enable per-user storage. |
--quick-test-for-ci | disabled | Quick startup test for CI. Exits immediately after initialization. |
This reference is based on ComfyUI comfy/cli_args.py. When upgrading ComfyUI, run python main.py --help or compare your local cli_args.py against this page to check for new or changed flags. 
