---
title: "Nano Banana 2.1"
description: "Nano Banana 2.1 makes and edits still images at low cost. It is the fast, high-volume member of the roasOS image family, best for iteration, large output sets and maskless edits."
url: https://docs.roasos.com/models/image/nano-banana-2.1
---
# Nano Banana 2.1
Family
`image`
· model
`nano-banana-2.1`
· catalog
`model-catalog@2026-10-06.v5`
· pricing
`customer-pricing@2026-11-05.v15`
.
## Endpoint
```http
POST https://api.roasos.com/v1/image/nano-banana-2.1
```
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](/concepts/jobs) and [Quotes and credits](/concepts/quotes-and-credits).
## Good at
Nano Banana 2.1 is Google's fast image generation and editing model. One 1K image costs 1 credit, against 2 for Nano Banana Pro. Use it to iterate on a concept, to make many variations, and to make a maskless edit of an existing image: send the source image as the only reference, state the change in the prompt, and set `aspect_ratio: "auto"` so the result keeps the source shape. It accepts the same identity, product and style roles as Nano Banana Pro. It does not do masked inpaint. Use Nano Banana Pro when the result is a final hero asset or when 4K output must hold fine detail.
## Pricing
The unit is one **image**. Pricing key: `nano-banana-2.1`.
| Request | Credits |
| ------------- | ------- |
| `1_image_1K` | 1 |
| `1_image_2K` | 2 |
| `1_image_4K` | 2 |
| `4_images_4K` | 8 |
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: `google/nano-banana-2.1` · `google/nano-banana-2.1/edit`.
## Request fields
| Field | Type | Required | Default | Rule |
| ---------------------- | --------- | -------- | ------- | ------------------------------------------------------------------------------- |
| `ad_look` | enum | no | — | `designed`, `native`, `ui` |
| `ad_set` | object | no | — | `{ id, index, total }` |
| `alter` | object | no | — | `{ mode, who, new_person, clothes, outfit, object, product, keep, multi_shot }` |
| `aspect_ratio` | enum | no | `1:1` | `auto`, `9:16`, `1:1`, `3:4`, `4:3`, `16:9`, `21:9` |
| `avatar_id` | string | no | — | UUID |
| `avatar_outfit` | string | no | — | ≤ 500 characters |
| `num_images` | integer | no | `1` | 1–4 |
| `product_id` | string | no | — | UUID |
| `product_images` | string\[] | no | — | ≤ 14 items; only in `edit` |
| `prompt` | string | no | — | ≥ 1 character; ≤ 8,000 characters |
| `prompt_mode` | enum | no | — | `wrapped`, `exact` |
| `quote_id` | string | no | — | UUID |
| `quote_only` | boolean | no | `false` | — |
| `references` | string\[] | no | — | ≤ 14 items; only in `edit` |
| `resolution` | enum | no | `1K` | `1K`, `2K`, `4K` |
| `seed` | integer | no | — | -2147483648–2147483647 |
| `source_image` | string | no | — | https URL; ≤ 4,096 characters |
| `wait_timeout_seconds` | integer | no | `0` | 0–60 |
| `webhook_url` | string | no | — | https URL; ≤ 4,096 characters |
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
| Role | Items | Maximum size | Content types | Duration |
| ---------------- | ----- | ------------ | --------------------------------------- | -------- |
| `product_images` | ≤ 14 | 10 MB | `image/jpeg`, `image/png`, `image/webp` | — |
| `references` | ≤ 14 | 10 MB | `image/jpeg`, `image/png`, `image/webp` | — |
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`.
Each media URL must be an immutable object on
`https://cdn.roasos.com`
that your workspace owns. Any other URL gets
`400 reference_media_not_workspace_owned`
. Refer to
[Reference media and uploads](/concepts/reference-media)
to learn how to put a file there.
## Prompt
Limit: 8,000 characters for the caller; the wrapper counts toward the 10,000-character engine cap. No tag syntax; the worker orders the references and names the roles.
* Write one scene description with the camera, the light and the material named.
* For an edit, state the change only ("replace the sky with an overcast sky; keep everything else"), and set `aspect_ratio: "auto"`.
* Put identity and product rules in the media roles, not in the prompt text.
* Iterate here, then rerun the winning prompt on Nano Banana Pro for the final asset.
* Give rendered text inside quotation marks.
## 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` — not accepted by this public endpoint.
* `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.
* `thinking_level` — not accepted by this public endpoint.
* `video_url` — not accepted by this public endpoint.
* `audio_url` — not accepted by this public endpoint.
* `pdf_url` — 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`.
```json
{
"data": {
"id": "gen_…",
"kind": "image",
"model": "nano-banana-2.1",
"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.
cURL
JavaScript
Python
```bash
# 1. Quote. Nothing is spent.
curl -X POST https://api.roasos.com/v1/image/nano-banana-2.1 \
-H "Authorization: Bearer roasos_sk_live_..." \
-H "Idempotency-Key: 0f1c9e2a-nano-banana-2.1-0001" \
-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": 1, "expires_at": "...",
# "confirmation": { "model": "nano-banana-2.1", "example": "1_image_1K" } } }
# 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-2.1 \
-H "Authorization: Bearer roasos_sk_live_..." \
-H "Idempotency-Key: 0f1c9e2a-nano-banana-2.1-0001" \
-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": 1 } }
# 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_..."
```
```javascript
const key = process.env.ROASOS_API_KEY;
const url = "https://api.roasos.com/v1/image/nano-banana-2.1";
const idempotencyKey = "0f1c9e2a-nano-banana-2.1-0001";
const input = {
"prompt": "A woman holds the bottle at eye level in a bright kitchen, morning light, static camera."
};
const post = (payload) =>
fetch(url, {
method: "POST",
headers: {
Authorization: `Bearer ${key}`,
"Idempotency-Key": idempotencyKey,
"Content-Type": "application/json",
},
body: JSON.stringify(payload),
}).then((response) => response.json());
// 1. Quote. Nothing is spent.
const quote = await post({ quote_only: true, ...input });
console.log(quote.data.credits);
// 2. Run.
const job = await post({ quote_id: quote.data.quote_id, ...input });
// 3. Poll, then read the result.
let status = "queued";
while (status !== "completed" && status !== "failed" && status !== "canceled") {
await new Promise((done) => setTimeout(done, 3000));
const poll = await fetch(`${url.split("/v1")[0]}/v1/jobs/${job.data.id}/status`, {
headers: { Authorization: `Bearer ${key}` },
}).then((response) => response.json());
status = poll.data.status;
}
const result = await fetch(`${url.split("/v1")[0]}/v1/jobs/${job.data.id}/result`, {
headers: { Authorization: `Bearer ${key}` },
}).then((response) => response.json());
console.log(result.data.result);
```
```python
import os, time, requests
key = os.environ["ROASOS_API_KEY"]
url = "https://api.roasos.com/v1/image/nano-banana-2.1"
headers = {
"Authorization": f"Bearer {key}",
"Idempotency-Key": "0f1c9e2a-nano-banana-2.1-0001",
}
payload = {
"prompt": "A woman holds the bottle at eye level in a bright kitchen, morning light, static camera."
}
# 1. Quote. Nothing is spent.
quote = requests.post(url, headers=headers, json={"quote_only": True, **payload}).json()
print(quote["data"]["credits"])
# 2. Run.
job = requests.post(url, headers=headers, json={"quote_id": quote["data"]["quote_id"], **payload}).json()
job_id = job["data"]["id"]
# 3. Poll, then read the result.
jobs = "https://api.roasos.com/v1/jobs"
status = "queued"
while status not in ("completed", "failed", "canceled"):
time.sleep(3)
status = requests.get(f"{jobs}/{job_id}/status", headers=headers).json()["data"]["status"]
result = requests.get(f"{jobs}/{job_id}/result", headers=headers).json()
print(result["data"]["result"])
```
## 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-2.1", "prompt": "…", "options": { "aspect_ratio", "resolution", "num_outputs", "reference_images" (≤ 9), "seed" } }`. No `avatar_id`, `product_images` or `product_id` role today; the prompt is sent raw. The `resolution` values are `1K`, `2K` and `4K`. The default is `1K`. Today's `aspect_ratio` list is `auto, 9:16, 1:1, 3:4, 4:3, 16:9, 21:9`.
## See also
* [`llms.txt` for this model](https://docs.roasos.com/models/image/nano-banana-2.1/llms.txt) — the same facts as one plain-text file for an agent.
* `GET https://api.roasos.com/v1/catalog/nano-banana-2.1` — the machine-readable form: enums, defaults, limits and prices. Refer to the [API reference](/api-reference/overview).
* [Jobs](/concepts/jobs) — how to poll a job and read its result.
* Provider endpoints: `google/nano-banana-2.1` · `google/nano-banana-2.1/edit`.