Nano Banana 2.1

Nano Banana 2.1 (google/gemini-nano-banana-2.1) is Google’s image model update. Two endpoints: POST /v1/images/generations for text-to-image and POST /v1/images/edits for working from a reference image (up to 3 references). Prompt — up to 20,000 characters.

Parameters

Parameter	Value
model	google/gemini-nano-banana-2.1
Aspect ratios	1:1, 2:3, 3:2, 3:4, 4:3, 4:5, 5:4, 9:16, 16:9, 21:9, 1:4, 4:1, 1:8, 8:1
Resolutions	1k, 2k, 4k
References (/images/edits)	up to 3 images
Prompt cap	20,000 characters

The narrow 1:4/4:1/1:8/8:1 ratios are banners and ribbons; most models have nothing like them.

Examples

Text to image

Python

from openai import OpenAI

client = OpenAI(base_url="https://api.mixen.ai/v1", api_key="mxn-...")

img = client.images.generate(
    model="google/gemini-nano-banana-2.1",
    prompt="A cozy coffee shop in the evening, watercolor",
    aspect_ratio="16:9",
    resolution="2k",
)
print(img.data[0].b64_json[:50], "...")

cURL

curl https://api.mixen.ai/v1/images/generations \
  -H "Authorization: Bearer $MIXEN_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model": "google/gemini-nano-banana-2.1", "prompt": "A cozy coffee shop in the evening, watercolor", "aspect_ratio": "16:9", "resolution": "2k"}'

Editing from a reference

A multipart images/edits request: the reference image plus a text instruction.

curl https://api.mixen.ai/v1/images/edits \
  -H "Authorization: Bearer $MIXEN_API_KEY" \
  -F model=google/gemini-nano-banana-2.1 \
  -F image=@sketch.png \
  -F prompt="Color the sketch in a warm palette, keep the composition"

Pricing

$0.0675 per image — independent of aspect ratio and resolution. Showcase prices follow the live exchange rate — take the fresh value from the catalog.

Strengths and limitations

• 14 aspect ratios, including ultra-wide 1:4–8:1 — banners, covers, story ribbons.
• Reference editing and a long prompt (20,000 characters) — detailed scene directions.
• Paid: there is no free quota, every generation is charged from the balance.
• For quick drafts FLUX.3 Klein is cheaper — from $0.012.

All image models — in the catalog. The general workflow — images guide.