Image Generation

Generate images from text prompts. Quality tiers, aspect ratios, negative prompts, and batch generation.

FairStack offers 39 image models. This guide covers the key concepts.

Basic image generation

curl -X POST https://api.fairstack.ai/v1/generations/image \
  -H "Authorization: Bearer $FAIRSTACK_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model": "z-image-turbo", "input": {"prompt": "A serene mountain lake"}}'

Quality tiers

Tier	Example Model	Price	Best For
Standard	FLUX.2	$0.03/image	Marketing, social media
Premium	Nano Banana Pro	$0.1608/image	Professional, print quality
Low-cost	Z-Image Turbo	$0.0048/image	Prototyping, bulk generation

Aspect ratios

Most models support multiple aspect ratios: 1:1, 4:3, 16:9, 9:16, and more. Specify via the aspect_ratio or image_size parameter.

Negative prompts

Some models support negative prompts to exclude unwanted elements:

{
  "model": "seedream-4.5-t2i",
  "input": {
    "prompt": "A portrait photo, professional lighting",
    "negative_prompt": "blurry, low quality, watermark"
  }
}

Image editing

Upload a source image and describe what to change:

{
  "model": "flux-kontext-pro",
  "input": {
    "prompt": "Change the background to a beach",
    "image_url": "https://example.com/photo.jpg"
  }
}

Next steps

Image API Reference -- full endpoint documentation
Image Models -- browse all 39 image models
Model Catalog -- browse all models

SDKs Video Generation