mold

Generate images from text on your own GPU. No cloud, no Python, no fuss.

mold run "a cat riding a motorcycle through neon-lit streets"

That's it. Mold auto-downloads the model on first run and saves the image to your current directory.

Install

Nix (recommended)

# Run directly — no install needed
nix run github:utensils/mold -- run "a cat"

# Or add to your system
nix profile install github:utensils/mold

From source

cargo build --release -p mold-cli --features cuda    # Linux (NVIDIA)
cargo build --release -p mold-cli --features metal   # macOS (Apple Silicon)

Usage

# Generate an image
mold run "a sunset over mountains"

# Pick a model
mold run flux-dev:q4 "a turtle in the desert"
mold run sdxl-turbo "espresso in a tiny cup"
mold run dreamshaper-v8 "fantasy castle on a cliff"

# Reproducible results (the logo above was generated this way)
mold run z-image-turbo:bf16 "A minimal modern logo for 'mold' on a solid black background. A stylized casting mold shape formed from smooth gradient lines transitioning from cyan to magenta. The negative space inside the mold reveals a glowing latent grid pattern suggesting AI diffusion. Bold lowercase 'mold' typography below in clean sans-serif. Flat vector style, no photorealism" --seed 1337

# Custom size and steps
mold run "a portrait" --width 768 --height 1024 --steps 30

Piping

Mold is pipe-friendly in both directions. When stdout is not a terminal, raw image bytes go to stdout and status/progress goes to stderr.

# Pipe output to an image viewer
mold run "neon cityscape" | viu -

# Pipe prompt from stdin
echo "a cat riding a motorcycle" | mold run flux-schnell

# Chain with other tools
cat prompt.txt | mold run z-image-turbo --seed 42 | convert - -resize 512x512 thumbnail.png

# Pipe in and out
echo "cyberpunk samurai" | mold run flux-dev:q4 | viu -

Manage models

mold pull flux-schnell:q8    # Download a model
mold list                    # See what you have
mold info flux-dev:q4        # Model details + disk usage
mold rm dreamshaper-v8       # Remove a model

Remote rendering

Run mold on a beefy GPU server, generate from anywhere:

# On your GPU server
mold serve

# From your laptop
MOLD_HOST=http://gpu-server:7680 mold run "a cat"

Models

FLUX (best quality)

SDXL (fast + flexible)

SD 1.5 (lightweight)

SD 3.5

Z-Image

Bare names default to :q8 for FLUX/Z-Image or :fp16 for SD1.5/SDXL. So mold run flux-schnell "a cat" just works.

Server API

When running mold serve, you get a REST API:

# Generate an image
curl -X POST http://localhost:7680/api/generate \
  -H "Content-Type: application/json" \
  -d '{"prompt": "a glowing robot"}' \
  -o robot.png

# Check status
curl http://localhost:7680/api/status

# List models
curl http://localhost:7680/api/models

# Interactive docs
open http://localhost:7680/api/docs

Shell completions

source <(mold completions bash)    # bash
source <(mold completions zsh)     # zsh
mold completions fish | source     # fish

Requirements

• NVIDIA GPU with CUDA or Apple Silicon with Metal
• Models auto-download on first use (~2-12GB depending on model)

How it works

Mold is a single Rust binary built on candle — a pure Rust ML framework. No Python runtime, no libtorch, no ONNX. Just your GPU doing math.

mold run "a cat"
  │
  ├─ Server running? → send request over HTTP
  │
  └─ No server? → load model locally on GPU
       ├─ Encode prompt (T5/CLIP text encoders)
       ├─ Denoise latent (transformer/UNet)
       ├─ Decode pixels (VAE)
       └─ Save PNG