This guide shows how to generate images using Nano Banana 2 via the Leonardo.AI REST API.

Sample Request

curl --location 'https://cloud.leonardo.ai/api/rest/v2/generations' \
     --header 'authorization: Bearer {api-key}' \
     --header 'Content-Type: application/json' \
     --data '{
       "model": "nano-banana-2",
       "parameters": {
           "width": 1024,
           "height": 1024,
           "prompt": "a portrait-style photograph featuring a koala",
           "quantity": 1,
           "style_ids": [
                "111dc692-d470-4eec-b791-3475abac4c46"
           ],
           "prompt_enhance": "OFF"
        },
        "public": false
      }'

Recipe

API Request Endpoint, Headers, Parameters

Endpoint

https://cloud.leonardo.ai/api/rest/v2/generations

Headers

--header "accept: application/json" \
--header "authorization: Bearer <YOUR_API_KEY>" \
--header "content-type: application/json"

Body Parameters

Parameter	Type	Definition
guidances	`object`	Optional. Object defining image guidance inputs that influence the generated result.
guidances.image_reference	`array`	Optional. Array of up to 6 reference images. Each reference includes image.id, image.type (`GENERATED` or `UPLOADED`), and strength (`LOW`, `MID`, `HIGH`).
height	`integer`	Optional. Height input resolution. Refer to the table below for valid height and width pairs.
model	`string`	Required. Model identifier. Refer to the table below for a list of models. Set to `nano-banana-2`.
prompt	`string`	Required. Text prompt describing what image you want the model to generate. Maximum of 5000 characters.
prompt_enhance	`string`	Optional. Enables prompt enhancement when set to `"ON"`; disabled when set to `"OFF"`.
public	`boolean`	Optional. Boolean flag that determines whether the generation is public (`true`) or private (`false`).
quantity	`integer`	Optional. Number of images to generate in a single request. Default is 1, maximum is 8.
seed	`integer`	Optional. Apply a fixed seed to maintain consistency across generation sets.
style_ids	`array`	Optional. Array of style UUIDs used to apply preset artistic styles to the output.
width	`integer`	Optional. Width input resolution. Refer to the table below for valid height and width pairs.

List of Height and Width

Model	Height	Width
Nano Banana 2	672, 768, 848, 896, 928, 1024, 1152, 1200, 1264, 1344, 1376, 1536, 1696, 1792, 1856, 2048, 2304, 2400, 2528, 2688, 2752, 3072, 3392, 3584, 3712, 4096, 4608, 4800, 5056, 5504	768, 848, 896, 928, 1024, 1152, 1200, 1264, 1376, 1536, 1584, 1696, 1792, 1856, 2048, 2304, 2400, 2528, 2752, 3072, 3168, 3392, 3584, 3712, 4096, 4608, 4800, 5056, 5504, 6336

Dimensions

The API accepts width and height parameters in the following aspect ratio combinations:

Aspect Ratio	1K (Small)	2K (Medium)	4K (Large)
1:1	1024 × 1024	2048 × 2048	4096 × 4096
2:3	848 × 1264	1696 × 2528	3392 × 5056
3:2	1264 × 848	2528 × 1696	5056 × 3392
3:4	896 × 1200	1792 × 2400	3584 × 4800
4:3	1200 × 896	2400 × 1792	4800 × 3584
4:5	928 × 1152	1856 × 2304	3712 × 4608
5:4	1152 × 928	2304 × 1856	4608 × 3712
9:16	768 × 1376	1536 × 2752	3072 × 5504
16:9	1376 × 768	2752 × 1536	5504 × 3072
21:9	1584 × 672	3168 × 1344	6336 × 2688

Important: width and height parameters are validated independently, but their combination is not validated against the supported aspect ratio pairs. If both values are individually valid but do not match one of the supported width–height pairs listed in the table above, the request will still be accepted. In this case, the aspect ratio passed to the model will silently default to 1:1, and no validation error will be returned.

To ensure the intended aspect ratio is used, always provide a width and height combination that exactly matches one of the supported pairs.

A width and height value of 0 and 0 instructs the system to attempt to match the aspect ratio of the input reference image.

List of Style IDs

Preset Style	UUID
3D Render	`debdf72a-91a4-467b-bf61-cc02bdeb69c6`
Acrylic	`3cbb655a-7ca4-463f-b697-8a03ad67327c`
Creative	`6fedbf1f-4a17-45ec-84fb-92fe524a29ef`
Dynamic	`111dc692-d470-4eec-b791-3475abac4c46`
Fashion	`594c4a08-a522-4e0e-b7ff-e4dac4b6b622`
Game Concept	`09d2b5b5-d7c5-4c02-905d-9f84051640f4`
Graphic Design 2D	`703d6fe5-7f1c-4a9e-8da0-5331f214d5cf`
Graphic Design 3D	`7d7c2bc5-4b12-4ac3-81a9-630057e9e89f`
Illustration	`645e4195-f63d-4715-a3f2-3fb1e6eb8c70`
None	`556c1ee5-ec38-42e8-955a-1e82dad0ffa1`
Portrait	`8e2bc543-6ee2-45f9-bcd9-594b6ce84dcd`
Portrait Cinematic	`4edb03c9-8a26-4041-9d01-f85b5d4abd71`
Portrait Fashion	`0d34f8e1-46d4-428f-8ddd-4b11811fa7c9`
Pro B&W photography	`22a9a7d2-2166-4d86-80ff-22e2643adbcf`
Pro Color Photography	`7c3f932b-a572-47cb-9b9b-f20211e63b5b`
Pro Film Photography	`581ba6d6-5aac-4492-bebe-54c424a0d46e`
Ray Traced	`b504f83c-3326-4947-82e1-7fe9e839ec0f`
Stock Photo	`5bdc3f2a-1be6-4d1c-8e77-992a30824a2c`
Watercolor	`1db308ce-c7ad-4d10-96fd-592fa6b75cc4`

Image Guidance

Sample Request

curl --location 'https://cloud.leonardo.ai/api/rest/v2/generations' \
     --header 'authorization: Bearer {api-key}' \
     --header 'Content-Type: application/json' \
     --data '{
       "model": "nano-banana-2",
       "parameters": {
           "width": 1024,
           "height": 1024,
           "prompt": "A koala is wearing a colourful Hawaiian shirt",
           "quantity": 1,
           "guidances": {
               "image_reference": [
                   {
                       "image": {
                           "id": "fc6f78c6-e7ac-491b-ad26-01f6843db870",
                           "type": "GENERATED"
                       },
                       "strength": "MID"
                   },
                   {
                       "image": {
                           "id": "a8e374dd-52f8-4236-ad9e-99b1f601fa3a",
                           "type": "UPLOADED"
                       },
                       "strength": "MID"
                   }
               ]
           },
           "style_ids": [
               "111dc692-d470-4eec-b791-3475abac4c46"
           ],
           "prompt_enhance": "OFF"
       },
       "public": false
   }'