Text-to-Image

Edit, transform, and compose images using Nano Banana Flash and Nano Banana Pro — Google Gemini-powered models that understand both text and images simultaneously.

Text to image API

POST /api/v1/images/generate

Headers

Name	Value
Content-Type	application/json
Authorization	Bearer <token>

---

Models at a Glance

Model ID	Name	Engine	Speed	Max Resolution	Max Images	Key Feature
vertex/nano-banana-flash	Nano Banana 2	Gemini Flash	Fast	4K	10	Search grounding
vertex/nano-banana-pro	Nano Banana Pro	Gemini Pro	Standard	4K	10	Text rendering, character consistency
vertex/imagen-4	Imagen 4	Imagen 4.0	Standard	2K	4	Balanced quality + adherence
vertex/imagen-4-fast	Imagen 4 Fast	Imagen 4.0 Fast	Fastest	~1K	4	Lowest cost, highest throughput
vertex/imagen-4-ultra	Imagen 4 Ultra	Imagen 4.0 Ultra	Slowest	2K	4	Highest quality, complex prompts

---

Nano Banana Flash — vertex/nano-banana-flash

Powered by Gemini 3.1 Flash. Best for fast generation, real-time search-grounded accuracy, high-volume workflows, and image-to-image editing.

Minimal

{
  "model": "vertex/nano-banana-flash",
  "prompt": "A cozy Japanese ramen shop on a rainy night, steam rising from bowls, warm ambient lighting"
}

Standard

{
  "model": "vertex/nano-banana-flash",
  "prompt": "A hyperrealistic macro photograph of a butterfly on a lavender flower, water droplets on wings, golden hour light",
  "aspect_ratio": "4:3",
  "quality": "2K",
  "num_images": 1,
  "temperature": 1.0,
  "seed": 42
}

With Search Grounding

Enable real-time Google Search so the model generates factually and visually accurate content — real architecture, real locations, real brand identities.

{
  "model": "vertex/nano-banana-flash",
  "prompt": "The interior of the Pantheon in Rome with sunlight streaming through the oculus, accurate architecture and proportions",
  "aspect_ratio": "4:3",
  "quality": "2K",
  "use_search_grounding": true
}

Multiple Variations

{
  "model": "vertex/nano-banana-flash",
  "prompt": "A minimalist flat illustration of a coffee cup with steam, pastel color palette, icon style",
  "aspect_ratio": "1:1",
  "quality": "1K",
  "num_images": 4,
  "temperature": 1.1
}

Parameters

Field	Type	Default	Options	Description
prompt	string	required	max 4000 chars	Text description of the image
aspect_ratio	string	1:1	See Aspect Ratio Support	Output dimensions
quality	string	2K	512, 1K, 2K, 4K	Output resolution. 4K triggers higher billing rate
num_images	integer	1	1–10	Variations per call
temperature	number	1.0	0–2	Creativity. Lower = faithful, higher = creative
seed	integer	—	any integer	Reproducibility. Same seed + prompt = same image
use_search_grounding	boolean	false	—	Real-time Google Search context for accuracy
celery	boolean	false	—	true = async, returns task_id immediately

---

Nano Banana Pro — vertex/nano-banana-pro

Powered by Gemini 3 Pro. Best for production output, multi-language text rendering in images, 4K exports, and consistent character/product depiction across generations.

Minimal

{
  "model": "vertex/nano-banana-pro",
  "prompt": "A luxury watch on a black marble surface, dramatic spotlight lighting, product photography"
}

Standard

{
  "model": "vertex/nano-banana-pro",
  "prompt": "A cinema-quality portrait of a woman in a traditional Japanese kimono standing in a cherry blossom garden, shallow depth of field, golden hour lighting",
  "aspect_ratio": "3:4",
  "quality": "4K",
  "num_images": 1,
  "temperature": 0.9,
  "seed": 12345
}

With Text in Image

Nano Banana Pro renders text in images with high accuracy across multiple languages.

{
  "model": "vertex/nano-banana-pro",
  "prompt": "A clean coffee shop menu board with the text 'Espresso $3.50', 'Latte $4.50', 'Cappuccino $4.00' written in elegant chalk lettering on a dark background",
  "aspect_ratio": "3:4",
  "quality": "2K",
  "temperature": 0.8
}

With Reference Images (Character / Product Consistency)

{
  "model": "vertex/nano-banana-pro",
  "prompt": "Generate this character standing in a futuristic neon-lit city plaza at night. Keep exact face, hairstyle, and outfit from the references.",
  "reference_images": [
    {
      "url": "https://your-cdn.com/character-front.jpg",
      "description": "Character front view — match face, hair color, and facial features exactly"
    },
    {
      "url": "https://your-cdn.com/character-outfit.jpg",
      "description": "Character outfit — match the denim jacket, white t-shirt, and black jeans"
    }
  ],
  "quality": "2K",
  "aspect_ratio": "9:16",
  "temperature": 0.85
}

Parameters

Field	Type	Default	Options	Description
prompt	string	required	max 4000 chars	Text description of the image
aspect_ratio	string	1:1	See Aspect Ratio Support	Output dimensions
quality	string	2K	1K, 2K, 4K	Output resolution. 4K triggers higher billing rate
num_images	integer	1	1–10	Variations per call
temperature	number	1.0	0–2	Creativity. Lower = faithful, higher = creative
seed	integer	—	any integer	Reproducibility
reference_images	object[]	—	max 14	Visual references for consistency. Each has url and optional description (max 500 chars)
celery	boolean	false	—	true = async processing

---

Imagen 4 — vertex/imagen-4

Powered by Imagen 4.0. Best for general-purpose generation with strict prompt adherence, multilingual support, and configurable safety controls.

Minimal

{
  "model": "vertex/imagen-4",
  "prompt": "A hyperrealistic close-up of a dew-covered spider web at dawn, macro photography"
}

Standard

{
  "model": "vertex/imagen-4",
  "prompt": "A sweeping landscape of the Scottish Highlands at golden hour, rolling heather-covered hills, dramatic storm clouds breaking, a lone castle in the distance",
  "aspect_ratio": "16:9",
  "num_images": 1,
  "image_size": "2K"
}

With All Safety Controls

{
  "model": "vertex/imagen-4",
  "prompt": "A professional portrait of a businessperson in a modern office, natural window light, confident expression",
  "aspect_ratio": "3:4",
  "image_size": "2K",
  "num_images": 2,
  "output_compression_quality": 90,
  "person_generation": "allow_adult",
  "safety_filter_level": "block_medium_and_above",
  "enhance_prompt": false,
  "add_watermark": false
}

---

Imagen 4 Fast — vertex/imagen-4-fast

Powered by Imagen 4.0 Fast. Best for bulk generation, rapid prototyping, and cost-sensitive workloads. Fixed to approximately 1K resolution.

Minimal

{
  "model": "vertex/imagen-4-fast",
  "prompt": "A vibrant flat illustration of a bicycle in a sunny park, digital art style"
}

Standard

{
  "model": "vertex/imagen-4-fast",
  "prompt": "A simple icon of a shield with a checkmark, flat design, blue and white, clean vector style",
  "aspect_ratio": "1:1",
  "num_images": 4
}

Batch Generation

{
  "model": "vertex/imagen-4-fast",
  "prompt": "A colorful abstract geometric background pattern, modern gradient, suitable for mobile app splash screen",
  "aspect_ratio": "9:16",
  "num_images": 4,
  "celery": true
}

---

Imagen 4 Ultra — vertex/imagen-4-ultra

Powered by Imagen 4.0 Ultra. Best for the highest quality outputs, complex multi-element compositions, and strict instruction following. Use when quality is more important than speed or cost.

Minimal

{
  "model": "vertex/imagen-4-ultra",
  "prompt": "A breathtakingly detailed oil painting of a medieval port city at twilight, torchlit cobblestone streets, galleons in harbor, figures in period clothing"
}

Standard

{
  "model": "vertex/imagen-4-ultra",
  "prompt": "A hyperrealistic underwater scene: a coral reef ecosystem at depth, shafts of turquoise sunlight filtering through the surface, diverse marine life including clownfish, sea turtles, and manta rays, razor-sharp focus throughout the frame",
  "aspect_ratio": "16:9",
  "image_size": "2K",
  "num_images": 1
}

Maximum Quality

{
  "model": "vertex/imagen-4-ultra",
  "prompt": "A sweeping aerial panorama of the Dolomites in Italy at sunrise, snow-capped peaks glowing pink and orange, deep valleys in morning shadow, a winding mountain road visible far below, cinematic 8K quality",
  "aspect_ratio": "16:9",
  "image_size": "2K",
  "num_images": 1,
  "enhance_prompt": false,
  "add_watermark": false,
  "safety_filter_level": "block_medium_and_above"
}

---

Aspect Ratio Support

Ratio	NB Flash	NB Pro	Imagen 4 / Fast / Ultra
1:1	Yes	Yes	Yes
4:3	Yes	Yes	Yes
3:4	Yes	Yes	Yes
16:9	Yes	Yes	Yes
9:16	Yes	Yes	Yes
3:2	Yes	Yes	—
2:3	Yes	Yes	—
21:9	Yes	Yes	—
1:4	Yes	Yes	—
4:1	Yes	Yes	—
5:4	Yes	Yes	—
4:5	Yes	Yes	—