Avatar · Nano Banana Pro

Endpoint

POST https://api.roasos.com/v1/avatar/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

Use this endpoint to create a consistent person for a campaign. Two sequential Nano Banana Pro calls generate a 4K vertical 2:3 original full-body image, then a matching 4K landscape 16:9 sheet using that original image as the reference. The original and sheet use a pure white seamless studio background. The sheet shows full-body front, full-body back, and a close-up frontal face. Realistic characters use natural facial texture and soft dimensional studio light; supplied character details and non-photographic styles are preserved. Cropping derives the individual views without additional image generation calls. Use manual mode with a description to invent a character; use reference mode with 1–5 photos to anchor the character's appearance. Supported image, scene, and reference-video models use the sheet as the identity reference. Kling identity elements pair the frontal crop with the sheet. Lipsync uses a single frontal crop. Provider face-reference restrictions still apply.

Pricing

The unit is one avatar. 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

• manual
• reference

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:

• reference_images — the source images the generation is built from

Every other role is refused: avatar_id, elements, product_id, product_images, references, 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

Describe one adult character in description, up to 1,000 characters. The worker adds the original-image and three-panel sheet instructions; you do not need to request separate photos or write image tags.

• Describe appearance, build, hair, skin tone, wardrobe, and visual style.
• Specify the wardrobe you want preserved across the sheet.
• Keep scene and product direction for later image or scene requests.
• In reference mode, let the supplied photos anchor identity and describe details they do not show.

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 jpeg.
• 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.
• aspect_ratio — pinned to 2:3 original image; 16:9 reference sheet.
• resolution — pinned to 4K.
• num_images — pinned to 1 per stage; 2 sequential stages.
• seed — pinned to derived from the Idempotency-Key.

Result

The result kind is avatar. Always present: avatar_id, images. Present when the run makes it: full_body_url, portrait_url, reference_sheet.

{
  "data": {
    "id": "gen_…",
    "kind": "avatar",
    "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": {},
      "portrait_url": "https://cdn.roasos.com/workspaces/ws_01/portrait_url",
      "reference_sheet": "https://cdn.roasos.com/workspaces/ws_01/reference_sheet"
    }
  }
}

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/avatar/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,"description":"A woman in her late twenties, shoulder-length dark hair, plain grey t-shirt, neutral expression."}'
# 200 { "data": { "kind": "quote", "quote_id": "q_7Hk...", "credits": 20, "expires_at": "...",
#        "confirmation": { "model": "nano-banana-pro", "example": "4K_original_and_sheet" } } }

# 2. Run. Same body, same Idempotency-Key, quote_id in place of quote_only.
curl -X POST https://api.roasos.com/v1/avatar/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...","description":"A woman in her late twenties, shoulder-length dark hair, plain grey t-shirt, neutral expression."}'
# 201 { "data": { "id": "gen_...", "status": "queued", "credits_reserved": 20 } }

# 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_..."

Today

POST /v1/avatar/nano-banana-pro is the creation endpoint. Request quote_only first, then submit the same fields with quote_id and the same Idempotency-Key. The response is an avatar job. Its completed result exposes avatar_id, reference_sheet, portrait_url, and full_body_url. The full_body_url is the original image; portrait_url is the frontal face crop. Poll GET /v1/avatars/{avatar_id} until the saved avatar is available; publication may finish shortly after rendering. GET /v1/avatars lists saved identities and DELETE /v1/avatars/{id} removes one. One quote covers both 10-credit generation stages, for 20 credits total. There is no separate sheet purchase step. Existing avatars remain usable with their original reference images.

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.