Flux1 AIDevelopers
Flux1 AI API docs
Image generation

Nano Banana Pro

Generate and edit at 2K or 4K, with control over typography and composition.

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-pro
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: 1:1

auto1:12:33:23:44:34:55:49:1616:921:9
resolutionstringoptional

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

Default: 2K

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.