Nano Banana Pro

Endpoint

POST https://api.roasos.com/v1/image/nano-banana-pro

Send your API key as a bearer token. The key needs the scope api:write. Every paid request also needs an Idempotency-Key header.

The envelope fields quote_only, quote_id, webhook_url and wait_timeout_seconds behave the same on each model endpoint. Refer to Jobs and Quotes and credits.

Good at

Nano Banana Pro is Google's state-of-the-art image generation and editing model (fal tags: realism, typography). Use it for the final hero image, for a person who must look the same across images, and for a product that must keep its exact label and shape. It holds up to 14 reference images and it follows a long scene description with camera, light and material named. It renders 4K when fine detail matters. It is the only image model that the scene and avatar endpoints use. It does not do masked inpaint; use /v1/image-edit/gpt-image-2.5 for that.

Pricing

The unit is one image. Pricing key: nano-banana-pro.

The credits come from the roasOS pricing table. No other field changes the price. To get the exact price of your request, send it with quote_only: true first.

Modes

• text-to-image
• edit

roasOS selects the mode from the media fields of your request. You do not send a mode.

Provider endpoints: fal-ai/nano-banana-pro · fal-ai/nano-banana-pro/edit.

Request fields

The schema is strict. A field that is not in this table gets 400 unsupported_option. The field names are the roasOS role names. One role has one name in every family.

Media

This endpoint accepts these media roles:

• avatar_id — identity; the saved character reference sheet, with a derived portrait only where the model requires a single face or source frame
• product_id — product; resolves to the product image list
• product_images — product reference images
• references — style and appearance references

Every other role is refused: elements, reference_images, image_url, end_image_url, scene_id, scene_image, video_urls, video_url, audio_urls, audio_url, voice_id. A refused role gets 400 unsupported_option.

Prompt

Limit: 8,000 characters for the caller. The worker wrapper counts toward the 10,000-character engine cap. No tag syntax; the worker orders the references and names the roles.

• Write one scene: subject, action, setting, light, camera, material.
• Put identity and product rules in the media roles, not in the prompt text. The wrapper tells the model which image is the person, which is the product, and which is style only.
• Say what the person does and where the product is; do not describe the person's face.
• Give the exact text to render inside quotation marks.
• State the framing (close-up, half body, full body) and the aspect ratio in words when it matters.
• On a bad result, write a new prompt that names the fix; do not resend the same payload.

Not exposed

These catalog entries describe omitted inputs, pinned values and source constraints. They do not imply that the provider accepts every listed field.

• output_format — pinned to png.
• safety_tolerance — pinned to 4.
• enable_web_search — pinned to false.
• limit_generations — pinned to true.
• system_prompt — not accepted by this public endpoint.
• sync_mode — not accepted by this public endpoint.

Result

The result kind is image. Always present: nothing. Present when the run makes it: avatar_id, full_body_url, images, portrait_url, provider_seed, reference_sheet, url.

{
  "data": {
    "id": "gen_…",
    "kind": "image",
    "model": "nano-banana-pro",
    "status": "completed",
    "result": {
      "avatar_id": "00000000-0000-4000-8000-000000000000",
      "full_body_url": "https://cdn.roasos.com/workspaces/ws_01/full_body_url",
      "images": [
        "https://cdn.roasos.com/workspaces/ws_01/images-1.png"
      ],
      "portrait_url": "https://cdn.roasos.com/workspaces/ws_01/portrait_url",
      "provider_seed": 0,
      "reference_sheet": "https://cdn.roasos.com/workspaces/ws_01/reference_sheet",
      "url": "https://cdn.roasos.com/workspaces/ws_01/result"
    }
  }
}

The files are immutable objects on https://cdn.roasos.com. A result URL is a valid media input for your next request.

Example

The three steps are always the same: quote, run, poll.

# 1. Quote. Nothing is spent.
curl -X POST https://api.roasos.com/v1/image/nano-banana-pro \
  -H "Authorization: Bearer roasos_sk_live_..." \
  -H "Idempotency-Key: 0f1c9e2a-nano-banana-pro-0001" \
  -H "Content-Type: application/json" \
  -d '{"quote_only":true,"prompt":"A woman holds the bottle at eye level in a bright kitchen, morning light, static camera."}'
# 200 { "data": { "kind": "quote", "quote_id": "q_7Hk...", "credits": 2, "expires_at": "...",
#        "confirmation": { "model": "nano-banana-pro", "example": "1_image_2K" } } }

# 2. Run. Same body, same Idempotency-Key, quote_id in place of quote_only.
curl -X POST https://api.roasos.com/v1/image/nano-banana-pro \
  -H "Authorization: Bearer roasos_sk_live_..." \
  -H "Idempotency-Key: 0f1c9e2a-nano-banana-pro-0001" \
  -H "Content-Type: application/json" \
  -d '{"quote_id":"q_7Hk...","prompt":"A woman holds the bottle at eye level in a bright kitchen, morning light, static camera."}'
# 201 { "data": { "id": "gen_...", "status": "queued", "credits_reserved": 2 } }

# 3. Poll, then read the result.
curl https://api.roasos.com/v1/jobs/gen_.../status -H "Authorization: Bearer roasos_sk_live_..."
curl https://api.roasos.com/v1/jobs/gen_.../result -H "Authorization: Bearer roasos_sk_live_..."

The deprecated path

POST /v1/generations still reaches this model for one minor version. It is deprecated. This is how it maps:

POST /v1/generations { "type": "image", "model": "nano-banana-pro", "prompt": "…", "options": { "aspect_ratio", "resolution", "num_outputs", "reference_images" (≤ 9), "seed" } }. Today's public API has no avatar_id, product_images or product_id role, and it sends the prompt raw (no placement wrapper). aspect_ratio on today's path is 1:1, 16:9, 9:16, 4:3, 3:4, 21:9 (no auto, 4:5, 5:4, 3:2, 2:3).

See also

• llms.txt for this model — the same facts as one plain-text file for an agent.
• GET https://api.roasos.com/v1/catalog/nano-banana-pro — the machine-readable form: enums, defaults, limits and prices. Refer to the API reference.
• Jobs — how to poll a job and read its result.
• Provider endpoints: fal-ai/nano-banana-pro · fal-ai/nano-banana-pro/edit.