Nano Banana 2 – Flux1 AI API

Generate and edit at 1K, 2K or 4K with up to 14 reference images and a wide range of aspect ratios.

POST/api/v1/generations

JSON requestAsynchronousOne image per request

Pricing depends on resolution. Select a tier in the example to see the cost. Reference images do not add an extra charge. Check credits_refunded to confirm a refund; unresolved submissions may require review.

Jump to request examples ↓

Authorization

Authorizationstringrequired

Bearer fx1_live_… — send your API key in the request header. API access requires administrator approval.

Idempotency-Keystringoptional

Use one unique value per generation and reuse it with the same body on retries. Printable ASCII, no spaces. A different body with the same key returns 409.

Maximum length: 128 characters

Manage API keys ↗

Request body

modelstringrequired

Use this exact model ID in the top-level request body.

nano-banana-2

promptstringrequired

Describe the image to create, or the changes to make to your reference images. Whitespace is trimmed.

Maximum length: 5,000 characters

imagesstring[]optional

Optional reference images. Use publicly accessible HTTPS URLs or data:image/* base64 URIs (up to 20,000,000 characters per entry). Omit for text-to-image.

Maximum items: 14

aspect_ratiostringoptional

Output width-to-height ratio. Auto lets the model choose.

Default: auto

auto1:12:33:23:44:34:55:49:1616:921:91:44:11:88:1

resolutionstringoptional

Output resolution tier; values are case-insensitive. Omit or leave empty to use the default.

Default: 1K

1K2K4K

Response & next step

A successful submission returns 202 and a generation id. Poll GET /api/v1/generations/{id} every 2–3 seconds until the status is succeeded or failed.

Read the image URL from output.images[0].url. On failure, inspect error and credits_refunded. Returned dimensions are optional.

Generation lifecycle →Error reference →

Build your request

10 credits / image

ModeResolution

Examples only. Run on your server with your API key.

# Set FLUX1_IDEMPOTENCY_KEY once per image; reuse it on retries.
curl --request POST 'https://flux1.ai/api/v1/generations' \
  --header "Authorization: Bearer $FLUX1_API_KEY" \
  --header 'Content-Type: application/json' \
  --header "Idempotency-Key: ${FLUX1_IDEMPOTENCY_KEY:?Set a unique key for this generation}" \
  --data '{
  "model": "nano-banana-2",
  "prompt": "A ceramic cup on a linen table, soft morning light",
  "aspect_ratio": "1:1",
  "resolution": "1K"
}'

202 · POST /api/v1/generations

{
  "id": "gen_example",
  "status": "queued",
  "model": "nano-banana-2",
  "media_type": "image",
  "credits": 10,
  "credits_refunded": false,
  "input": {
    "prompt": "A ceramic cup on a linen table, soft morning light",
    "aspect_ratio": "1:1",
    "resolution": "1K"
  },
  "output": null,
  "error": null,
  "created_at": "2026-09-07T08:00:00.000Z",
  "completed_at": null
}