Stable Diffusion API

Generate images using Stability AI’s Stable Diffusion models through the Runcrate API. No GPU setup, no model hosting — one API call, one image.

Available models

Model	Quality	Speed	Best for
SD 3.5 Large	High	Medium	Production images, detailed scenes
SD 3 Medium	Good	Fast	Prototyping, high-volume generation

Basic image generation

from runcrate import Runcrate

client = Runcrate(api_key="rc_live_YOUR_API_KEY")

image = client.models.generate_image(
    model="stabilityai/stable-diffusion-3-5-large",
    prompt="A serene Japanese garden in autumn, koi pond with stone bridge, "
           "golden maple leaves, soft morning mist, photorealistic",
    aspect_ratio="16:9",
)

image.data[0].save("japanese-garden.png")

import Runcrate from '@runcrate/sdk';

const rc = new Runcrate({ apiKey: 'rc_live_YOUR_API_KEY' });

const image = await rc.models.generateImage({
  model: 'stabilityai/stable-diffusion-3-5-large',
  prompt: 'A serene Japanese garden in autumn, koi pond, golden maple leaves, photorealistic',
  aspectRatio: '16:9',
});

await image.save('japanese-garden.png');

curl https://api.runcrate.ai/v1/images/generations \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer rc_live_YOUR_API_KEY" \
  -d '{
    "model": "stabilityai/stable-diffusion-3-5-large",
    "prompt": "A serene Japanese garden in autumn, golden maple leaves, photorealistic",
    "aspect_ratio": "16:9"
  }'

Using negative prompts

from runcrate import Runcrate

client = Runcrate(api_key="rc_live_YOUR_API_KEY")

image = client.models.generate_image(
    model="stabilityai/stable-diffusion-3-5-large",
    prompt="Professional headshot of a business executive, studio lighting, neutral background",
    negative_prompt="cartoon, illustration, anime, blurry, low quality, deformed",
    aspect_ratio="1:1",
)

image.data[0].save("headshot.png")

Controlling generation parameters

from runcrate import Runcrate

client = Runcrate(api_key="rc_live_YOUR_API_KEY")

image = client.models.generate_image(
    model="stabilityai/stable-diffusion-3-5-large",
    prompt="Detailed architectural blueprint of a modern house, clean lines, cross-section view",
    num_inference_steps=40,   # default ~28, higher = more detail
    guidance=7.5,             # how closely to follow the prompt
    seed=42,                  # reproducible results
)

image.data[0].save("blueprint.png")

Batch generation

from runcrate import Runcrate
from concurrent.futures import ThreadPoolExecutor

client = Runcrate(api_key="rc_live_YOUR_API_KEY")

products = [
    {"name": "candle", "prompt": "Luxury scented candle in matte black jar, warm lighting, product photography"},
    {"name": "notebook", "prompt": "Premium leather notebook on wooden desk, fountain pen, natural light"},
    {"name": "mug", "prompt": "Ceramic coffee mug with steam, dark moody background, product shot"},
]

def generate(p):
    image = client.models.generate_image(
        model="stabilityai/stable-diffusion-3-5-large",
        prompt=p["prompt"], aspect_ratio="1:1",
    )
    image.data[0].save(f"{p['name']}.png")
    print(f"Saved {p['name']}.png")

with ThreadPoolExecutor(max_workers=4) as pool:
    pool.map(generate, products)

SD 3.5 Large vs. SD 3 Medium

	SD 3.5 Large	SD 3 Medium
Detail	Fine textures, realistic lighting	Sufficient for most uses
Speed	Medium	Fast
Best for	Final production assets	Prototyping, high-volume

Tips

Negative prompts significantly improve quality — exclude common artifacts.
Seed parameter makes results reproducible. Save it for prompt iteration.
SD 3.5 Large for customer-facing images. SD 3 Medium for internal/prototype.
Aspect ratio options: 1:1, 16:9, 9:16, 4:3, 3:2.

Next steps

Image generation reference
AI Image Generation API — FLUX and multi-model comparison
Ideogram 3 API — best text rendering in images

Inference Examples

Compute Examples

Storage Examples

Stable Diffusion API

Available models

Basic image generation

Using negative prompts

Controlling generation parameters

Batch generation

SD 3.5 Large vs. SD 3 Medium

Tips

Next steps

​Available models

​Basic image generation

​Using negative prompts

​Controlling generation parameters

​Batch generation

​SD 3.5 Large vs. SD 3 Medium

​Tips

​Next steps

Available models

Basic image generation

Using negative prompts

Controlling generation parameters

Batch generation

SD 3.5 Large vs. SD 3 Medium

Tips

Next steps