how to use Nano Banana API: submit, poll, and handle the failure case

Submit

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":"..."}'

The model id is exactly nano-banana — a typo here returns 400 UNKNOWN_MODEL naming what you sent.

You get 202 Accepted with a job, not an image:

{
  "job_id": "abc123",
  "state": "queued",
  "model": "nano-banana",
  "credits_held": 4
}

credits_held is what this call reserved. It comes back in full if the job fails or you cancel it.

Collect the result

curl "https://genace.ai/api/v1/jobs/abc123?wait=30" \
  -H "Authorization: Bearer $GENACE_API_KEY"

wait blocks server-side for up to N seconds. There are three other ways to collect — webhook, SSE and a cron backstop — and which to use depends on what is calling you. See webhook vs polling.

The failure that will not throw

A failed job is a successful HTTP response describing a failure:

{ "state": "failed", "error": { "code": "UPSTREAM_EMPTY_RESULT" } }

raise_for_status() and equivalents see a 200 and move on. Check state, not the status code.

Parameters worth setting

n accepts 1–4 images per call.

Full reference in Nano Banana API parameters.

Models covered on this page

• Nano Banana