# Nano Banana 2.1 — OpenAI Images

> Generate and edit Nano Banana 2.1 images with OpenAI-style JSON requests, resolution and thinking controls, and URL results.

Canonical URL: https://docs.uniall.ai/models/image/nano-series/nano-banana-2-1/openai-format
Locale: en

## Overview

Use `nano-banana-2.1` to generate an image from text or edit up to 14 reference images. Each synchronous request returns one image URL. This format suits OpenAI Images clients and integrations that supply reference images as URLs.

## Endpoints

| Workflow | Method and path | Input |
| --- | --- | --- |
| Text to image | `POST /v1/images/generations` | A non-empty `prompt`. |
| Image editing | `POST /v1/images/edits` | A non-empty `prompt` and at least one reference image. |

The base URL is `https://api.uniall.ai`. Nano Banana 2.1 does not support `/v1/chat/completions` or `/v1/images/tasks`.

## Authentication

Use your UniAI user API key:

```http
Authorization: Bearer <UNIAI_API_KEY>
Content-Type: application/json
```

## Request Parameters

Place the main parameters at the top level of the JSON body.

| Parameter | Type | Required | Description |
| --- | --- | --- | --- |
| `model` | string | Yes | `nano-banana-2.1`. |
| `prompt` | string | Yes | Non-empty generation or editing instruction. |
| `resolution` | string | No | `1k`, `2k`, or `4k`; defaults to `1k`. Uppercase values are also accepted. |
| `aspect_ratio` | string | No | One of the 14 ratios below. If omitted, the ratio follows the reference image or generated content. |
| `thinking_level` | string | No | `minimal`, `medium`, or `high`; defaults to `medium`. |
| `images` | string[] | Conditional | Preferred reference-image field for editing. HTTP(S) URLs or complete image Data URLs. |
| `image` / `image_url` | string | Conditional | Alternative reference-image fields. HTTP(S) URL or complete image Data URL. |
| `image_urls` | string[] | Conditional | Alternative array of reference-image URLs or complete image Data URLs. |
| `n` | integer | No | Only `1` is accepted; each request returns one image. |
| `num_images` | integer | No | Compatible image-count field; only `1` is accepted. |
| `response_format` | string | No | Accepts `url` or `b64_json` for compatibility. This endpoint always returns a URL. |
| `output_format` | string | No | Accepts `png` or `jpeg` for compatibility. The actual format follows the result; conversion is not guaranteed. |

### Resolution And Aspect Ratio

Supported aspect ratios:

```markdown
1:1  1:4  1:8  2:3  3:2  3:4  4:1
4:3  4:5  5:4  8:1  9:16  16:9  21:9
```

Resolution is a tier, not a fixed longest-edge pixel count. For example, a non-square `1k` result can be `1376 × 768`. `0.5K`, `512`, and `8K` are unsupported.

### Reference Images And Compatibility Fields

Editing requires 1 to 14 reference images across all reference fields combined. PNG, JPEG, and WebP are supported. Input order and duplicate entries are preserved; duplicates count toward the 14-image limit. Reference URLs must be directly accessible to the service. A Data URL must include the image MIME type and Base64 prefix, such as `data:image/png;base64,...`.

Use JSON references for editing. Multipart file uploads are unsupported.

`resolution`, `thinking_level`, `num_images`, `output_format`, and `response_format` may also be placed in `extra_body` for compatibility. If a field appears both at the top level and in `extra_body`, its values must match. The examples use top-level parameters.

## Request Examples

### Text To Image

```bash
curl -X POST "https://api.uniall.ai/v1/images/generations" \
  -H "Authorization: Bearer <UNIAI_API_KEY>" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "nano-banana-2.1",
    "prompt": "Create a spring latte poster with a cream background and clear typography",
    "resolution": "2k",
    "aspect_ratio": "16:9",
    "thinking_level": "high",
    "n": 1
  }'
```

### Image Editing

```bash
curl -X POST "https://api.uniall.ai/v1/images/edits" \
  -H "Authorization: Bearer <UNIAI_API_KEY>" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "nano-banana-2.1",
    "prompt": "Keep the cup shape and color; replace the background with a bright cafe",
    "images": ["https://example.com/reference.png"],
    "resolution": "2k",
    "aspect_ratio": "4:5",
    "thinking_level": "medium",
    "n": 1
  }'
```

Replace the example URL with your reference image. Add references to `images` in the order described by your prompt.

## Response Example

```json
{
  "created": 1791676800,
  "data": [
    {
      "url": "https://example.com/generated.png"
    }
  ]
}
```

Read `data[0].url` from the completed response. Even if you send `response_format: "b64_json"`, this entry point returns a URL. Inspect the downloaded file to determine its actual image format.

The response is synchronous and has no task ID or polling step. A client timeout does not confirm that generation stopped; avoid automatically submitting the request again.

## Capability Limits And Common Errors

- Search is unavailable. Omit `tools`, `enable_web_search`, and `enable_image_search`; supplying them is rejected even when a search flag is `false`.
- `quality`, custom pixel dimensions through `size` or `custom_size`, masks, transparent backgrounds, `seed`, and streaming output are unsupported.
- An editing request without a reference image, more than 14 references, an unsupported resolution or aspect ratio, or a count other than `1` is invalid.
- Keep OpenAI field names in this request. Gemini `contents` and `generationConfig` belong to the [Gemini page](./gemini-format).
- `thinking_level` is available only for the new 2.1 integration. It is not enabled for `nano-banana-2`, `nano-banana-pro`, or fixed-resolution compatibility models.

## Related Pages

- [Nano Series](/models/image/nano-series)
- [Nano Banana 2.1 — Gemini generateContent](./gemini-format)
- [OpenAI Images Format for other Nano models](/models/image/nano-series/openai-format)