Nano Banana API key: what you are actually asking for

First, the thing that clears up most confusion: Nano Banana is the nickname for Google Gemini 2.5 Flash Image. It is not a separate product with its own console. A direct key means a Google key.

The alternative is an aggregator key that reaches it alongside other image models through one interface.

What a call costs

4 credits per image through Genace — the cheapest image model on the platform, which is why it is the default. At the Enterprise pack rate that is $0.040 per image, or $40 per thousand. Full ladder in Nano Banana API pricing.

Using the key

export GENACE_API_KEY=sk_xxx

curl -X POST https://genace.ai/api/v1/images/generations \
  -H "Authorization: Bearer $GENACE_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model":"nano-banana","prompt":"a red ceramic mug on a white table","n":2}'

Omit model entirely and you still get Nano Banana — it is the image default, chosen because an unspecified model should not be the expensive one.

Batching and the concurrency ceiling

n accepts 1 to 4 and multiplies cost linearly: four images cost 16 credits whether batched or not. There is no volume discount.

What batching does buy you is concurrency slots. Ceilings are per key:

Tier	Requests per minute	Concurrent jobs
Free	5	1
Pro	60	5

On the free tier you get one in-flight job. Four images in one call is one job; four separate calls is four, and three of them get 429 CONCURRENCY_LIMIT_EXCEEDED.

Verifying the key

curl https://genace.ai/api/v1/models -H "Authorization: Bearer $GENACE_API_KEY"

Authenticated, free, outside quota.

When to pay more

Nano Banana is positioned for conversational, iterative editing with character and scene consistency across turns. If you need legible text inside the image — logos, posters, typography — that is Ideogram v3’s specialty at 6 credits. Comparison in AI image generation API pricing compared.

Models covered on this page

• Nano Banana