liyangbing · Oct 9, 2026 · Oct 8, 2026
diff --git a/.vitepress/theme/OfficialNativeApiSidebar.vue b/.vitepress/theme/OfficialNativeApiSidebar.vue
@@ -56,6 +56,10 @@ const googleModels = [
     text: 'Gemini 3.1 Flash Image（Nano Banana 2）',
     link: '/model-api-reference/official-native-api/google/gemini-3.1-flash-image',
   },
+  {
+    text: 'Gemini Nano Banana 2.1（Nano Banana 2.1）',
+    link: '/model-api-reference/official-native-api/google/gemini-nano-banana-2.1',
+  },
 ]
 
 function normalize(path: string) {

diff --git a/api-reference/gemini-generate-content.md b/api-reference/gemini-generate-content.md
@@ -77,6 +77,7 @@ These image models have dedicated native GenerateContent mappings:
 
 - [Gemini 3 Pro Image（Nano Banana Pro）](/model-api-reference/official-native-api/google/gemini-3-pro-image)
 - [Gemini 3.1 Flash Image（Nano Banana 2）](/model-api-reference/official-native-api/google/gemini-3.1-flash-image)
+- [Gemini Nano Banana 2.1（Nano Banana 2.1）](/model-api-reference/official-native-api/google/gemini-nano-banana-2.1)
 
 For these mappings, SandBase forwards the request and response payloads without converting them through Chat
 Completions. This preserves image parts, response modalities, and provider-defined fields. Use the bare model name in

diff --git a/model-api-reference/official-native-api/google/gemini-3-pro-image.md b/model-api-reference/official-native-api/google/gemini-3-pro-image.md
@@ -83,6 +83,20 @@ Add the source image as an `inlineData` part next to the text instruction. Use t
 }
 ```
 
+## Billing
+
+Usage is billed per token at Google's standard list price:
+
+| Token type | Price (USD / 1M tokens) |
+|---|---|
+| Input (text and image) | $2.00 |
+| Output text and thinking | $12.00 |
+| Output image | $120.00 |
+
+One output image uses 1120 tokens at 1K and 2K and 2000 tokens at 4K, about $0.134 and $0.24 per image. Image tokens
+are taken from `usageMetadata.candidatesTokensDetails` (`modality: IMAGE`); the remaining output tokens are billed at
+the text rate.
+
 ## Response handling
 
 Read generated media from the returned candidate parts. Because this model uses native passthrough, provider-defined

diff --git a/model-api-reference/official-native-api/google/gemini-3.1-flash-image.md b/model-api-reference/official-native-api/google/gemini-3.1-flash-image.md
@@ -82,6 +82,20 @@ Add the source image as an `inlineData` part next to the text instruction. Use t
 }
 ```
 
+## Billing
+
+Usage is billed per token at Google's standard list price:
+
+| Token type | Price (USD / 1M tokens) |
+|---|---|
+| Input (text and image) | $0.50 |
+| Output text and thinking | $3.00 |
+| Output image | $60.00 |
+
+One output image uses 747 tokens at 0.5K, 1120 at 1K, 1680 at 2K and 2520 at 4K, about $0.045, $0.067, $0.101 and
+$0.151 per image. Image tokens are taken from `usageMetadata.candidatesTokensDetails` (`modality: IMAGE`); the
+remaining output tokens are billed at the text rate.
+
 ## Response handling
 
 Read generated media from the returned candidate parts. Because this model uses native passthrough, provider-defined

diff --git a/model-api-reference/official-native-api/google/gemini-nano-banana-2.1.md b/model-api-reference/official-native-api/google/gemini-nano-banana-2.1.md
@@ -0,0 +1,147 @@
+---
+title: "Gemini Nano Banana 2.1（Nano Banana 2.1）Native API Reference"
+description: "Native Gemini GenerateContent API reference for google/gemini-nano-banana-2.1 (Nano Banana 2.1) on SandBase."
+aside: false
+outline: false
+apiReference:
+  title: Gemini Nano Banana 2.1（Nano Banana 2.1）
+  operation: Gemini GenerateContent
+  method: POST
+  path: /v1beta/models/gemini-nano-banana-2.1:generateContent
+  description: Generate or edit images with Nano Banana 2.1 through the native Google Gemini protocol. SandBase preserves the provider request and response payload instead of converting it to Chat Completions.
+  groups:
+    - title: Request body
+      description: Send a native Gemini GenerateContent body. Provider-defined fields are passed through for this model.
+      fields:
+        - { name: contents, type: array, required: true, description: Gemini Content objects containing the prompt and optional input images. }
+        - { name: generationConfig.responseModalities, type: "array<string>", required: true, description: "Requested output modalities. Include IMAGE; include TEXT when you also want a text part." }
+        - { name: generationConfig.imageConfig.aspectRatio, type: string, required: false, description: "Output aspect ratio, for example 1:1, 16:9, 9:16, 21:9, 4:1 or 1:8." }
+        - { name: generationConfig.imageConfig.imageSize, type: string, required: false, description: "Output resolution: 1K, 2K or 4K. Nano Banana 2.1 has no 0.5K tier." }
+  examples:
+    - label: cURL
+      language: bash
+      code: |-
+        curl -X POST \
+          "https://api.sandbase.ai/v1beta/models/gemini-nano-banana-2.1:generateContent" \
+          -H "x-goog-api-key: $SANDBASE_API_KEY" \
+          -H "Content-Type: application/json" \
+          -d '{
+            "contents": [{
+              "role": "user",
+              "parts": [{"text": "Create a wide editorial illustration of a solar-powered city at sunrise."}]
+            }],
+            "generationConfig": {
+              "responseModalities": ["IMAGE"],
+              "imageConfig": {"aspectRatio": "16:9", "imageSize": "1K"}
+            }
+          }'
+  response:
+    status: 200 OK
+    code: |-
+      {
+        "candidates": [{
+          "content": {
+            "role": "model",
+            "parts": [
+              {"inlineData": {"mimeType": "image/jpeg", "data": "<base64-image>"}, "thoughtSignature": "<signature>"}
+            ]
+          },
+          "finishReason": "STOP",
+          "index": 0
+        }],
+        "usageMetadata": {
+          "promptTokenCount": 14,
+          "candidatesTokenCount": 1120,
+          "candidatesTokensDetails": [{"modality": "IMAGE", "tokenCount": 1120}],
+          "totalTokenCount": 1134
+        }
+      }
+seo:
+  modelName: "Gemini Nano Banana 2.1（Nano Banana 2.1）"
+  modelId: "google/gemini-nano-banana-2.1"
+  vendor: "Google"
+  vendorSlug: "google"
+  modelSlug: "gemini-nano-banana-2.1"
+  protocol: "Gemini GenerateContent API"
+  endpoint: "/v1beta/models/gemini-nano-banana-2.1:generateContent"
+  publishedAt: "2026-10-08T00:00:00Z"
+  capabilities: ["image_generation", "image_editing"]
+  category: "Official Native API"
+---
+
+<ApiReferencePage />
+
+## Edit an image
+
+Add the source image as an `inlineData` part next to the text instruction. Use the MIME type of the bytes you send:
+
+```json
+{
+  "contents": [{
+    "role": "user",
+    "parts": [
+      {"text": "Keep the subject unchanged and turn the background into a paper-cut landscape."},
+      {"inlineData": {"mimeType": "image/png", "data": "<base64-input-image>"}}
+    ]
+  }],
+  "generationConfig": {"responseModalities": ["IMAGE"], "imageConfig": {"imageSize": "1K"}}
+}
+```
+
+## Use the Google Gen AI SDK
+
+Point the official SDK at SandBase and use your SandBase API key:
+
+```python
+from google import genai
+from google.genai import types
+
+client = genai.Client(
+    api_key="YOUR_SANDBASE_API_KEY",
+    http_options=types.HttpOptions(base_url="https://api.sandbase.ai"),
+)
+
+response = client.models.generate_content(
+    model="gemini-nano-banana-2.1",
+    contents="Create a wide editorial illustration of a solar-powered city at sunrise.",
+    config=types.GenerateContentConfig(
+        response_modalities=["IMAGE"],
+        image_config=types.ImageConfig(aspect_ratio="16:9", image_size="1K"),
+    ),
+)
+
+for part in response.candidates[0].content.parts:
+    if part.inline_data:
+        with open("output.jpg", "wb") as f:
+            f.write(part.inline_data.data)
+```
+
+For streaming, call `:streamGenerateContent?alt=sse` (SDK: `generate_content_stream`) with the same body.
+
+## Billing
+
+Usage is billed per token at Google's standard list price:
+
+| Token type | Price (USD / 1M tokens) |
+|---|---|
+| Input (text and image) | $1.50 |
+| Output text and thinking | $7.50 |
+| Output image | $30.00 |
+
+One output image uses 1120 tokens at 1K, 1680 at 2K and 3780 at 4K, about $0.034, $0.050 and $0.113 per image.
+Image tokens are taken from `usageMetadata.candidatesTokensDetails` (`modality: IMAGE`); the remaining output tokens are
+billed at the text rate.
+
+## Response handling
+
+Read generated media from the returned candidate parts. Because this model uses native passthrough, provider-defined
+field casing and MIME metadata are returned as received. The output is usually JPEG; decode the base64 payload and
+verify the actual media bytes before choosing a file extension. Keep `thoughtSignature` when you send the turn back in
+multi-turn editing.
+
+## Official Google resources
+
+- [Gemini API documentation](https://ai.google.dev/gemini-api/docs)
+- [Image generation documentation](https://ai.google.dev/gemini-api/docs/image-generation)
+- [GenerateContent API reference](https://ai.google.dev/api/generate-content)
+- [Gemini API pricing](https://ai.google.dev/gemini-api/docs/pricing)
diff --git a/model-api-reference/official-native-api/index.md b/model-api-reference/official-native-api/index.md
@@ -30,6 +30,7 @@ GPT Image models use the native OpenAI Images API at `/v1/images/generations` an
 - [Gemini Omni 1.1 Flash Preview](/model-api-reference/official-native-api/google/gemini-omni-1.1-flash-preview)
 - [Gemini 3 Pro Image（Nano Banana Pro）](/model-api-reference/official-native-api/google/gemini-3-pro-image)
 - [Gemini 3.1 Flash Image（Nano Banana 2）](/model-api-reference/official-native-api/google/gemini-3.1-flash-image)
+- [Gemini Nano Banana 2.1（Nano Banana 2.1）](/model-api-reference/official-native-api/google/gemini-nano-banana-2.1)
 
 Gemini Omni models use the native Google Gemini Interactions protocol at `/v1beta/interactions`. The two image models
 use Google GenerateContent at `/v1beta/models/{model}:generateContent`; their native request and response payloads are