Nano Banana Pro API

Nano Banana Pro is Google's name for Gemini 3 Pro Image, released in November 2025. It generates from text or from up to 14 reference images, which makes it a strong pick for putting known people, products and styles into one scene. Output comes in 1K, 2K or 4K across 10 aspect ratios from 1:1 to 21:9, one image per request. Prompts can be up to 32,000 characters in English or Chinese.

Best for

• Group scenes built from several character or product photos
• 4K marketing visuals and key art
• Applying the look of a mood board to a new subject
• Infographics and explainer images that mix text with imagery

Prompting tips

• Refer to references by order: "the woman in image 1 wearing the jacket from image 3".
• The default ratio on Jantaris is 1:1, so set aspect_ratio on edits to match the frame you want.
• Draft at 1k (the default), then re-run the prompt you like at 2k or 4k.
• Describe the scene in full sentences rather than a list of keywords; that matches Google's own prompting guidance for Gemini image models.

FAQ

How much does Nano Banana Pro cost via API?

Jantaris bills from $0.0747 per image for this model from a prepaid balance. You see the estimate before submitting, and failed generations are not charged.

How many images can I send to Nano Banana Pro?

Up to 14 reference images per request. It returns one image per call, so send parallel requests when you want variations.

Nano Banana Pro or Nano Banana 2?

Pro is the higher tier. Nano Banana 2 is Gemini 3.1 Flash Image: it returns up to 4 images per call and adds extreme ratios like 8:1, which suits fast, high-volume work.

Can Nano Banana Pro replace Midjourney?

For many jobs, yes, and it has an official API with pay-per-image billing instead of a subscription. How it compares with Midjourney is covered in Midjourney alternatives with an API, with similar guides for Krea AI and Leonardo AI, and the full ranking of image models is in best AI image generator 2026.

Does Nano Banana Pro on Jantaris have limits like the Gemini app?

There is no plan with an image allowance that refills every few hours like in the Gemini app - you pay for each image from a balance that never expires. How the app limits differ from API access is covered in Nano Banana and Veo limits.

How to call Nano Banana Pro via API

curl https://jantaris.com/v1/generate?wait=60 \
  -H "Authorization: Bearer $JANTARIS_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "model": "nano-banana-pro",
  "input": {
    "prompt": "Product photo of a matte black ceramic coffee cup on a travertine table, soft window light, 50mm",
    "aspect_ratio": "1:1",
    "resolution": "1k"
  }
}'

import os, time, requests

API = "https://jantaris.com/v1"
H = {"Authorization": f"Bearer {os.environ['JANTARIS_API_KEY']}"}

task = requests.post(f"{API}/generate", headers=H, json={
    "model": "nano-banana-pro",
    "input": {
        "prompt": "Product photo of a matte black ceramic coffee cup on a travertine table, soft window light, 50mm",
        "aspect_ratio": "1:1",
        "resolution": "1k"
    }
}).json()
while task["status"] in ("queued", "running"):
    time.sleep(3)
    task = requests.get(f"{API}/tasks/{task['id']}", headers=H).json()

print(task["status"], task["cost"], [o["url"] for o in task["output"]])

const API = "https://jantaris.com/v1";
const headers = { Authorization: `Bearer ${process.env.JANTARIS_API_KEY}`, "Content-Type": "application/json" };

let task = await (await fetch(`${API}/generate`, {
  method: "POST",
  headers,
  body: JSON.stringify({
    "model": "nano-banana-pro",
    "input": {
      "prompt": "Product photo of a matte black ceramic coffee cup on a travertine table, soft window light, 50mm",
      "aspect_ratio": "1:1",
      "resolution": "1k"
    }
  }),
})).json();

while (task.status === "queued" || task.status === "running") {
  await new Promise((r) => setTimeout(r, 3000));
  task = await (await fetch(`${API}/tasks/${task.id}`, { headers })).json();
}
console.log(task.status, task.cost, task.output.map((o) => o.url));

Parameters

The same schema is available from GET /v1/models/nano-banana-pro.