> ## Documentation Index
> Fetch the complete documentation index at: https://docs.gravitex.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Gemini Native (Image)

> Gemini generateContent and Chat Completions image generation

## Introduction

Gemini images can be requested via:

* **Gemini native**: `POST /v1beta/models/{model}:generateContent` with `responseModalities: ["IMAGE"]` and `imageConfig`
* **OpenAI-compatible**: `POST /v1/images/generations` — see [Gemini OpenAI format (Images)](/en/api-reference/endpoint/nano-banana) — or `POST /v1/chat/completions` — see [Gemini OpenAI format (Chat)](/en/api-reference/endpoint/gemini-chat-openai) appendix

## Authentication

<ParamField header="Authorization" type="string" required>
  Bearer Token, e.g. `Bearer sk-xxxxxxxxxx`
</ParamField>

## Request examples

<Tabs>
  <Tab title="generateContent">
    ```bash theme={null}
    curl -X POST "https://api.gravitex.ai/v1beta/models/gemini-2.5-flash-image:generateContent" \
      -H "Authorization: Bearer sk-xxxxxxxxxx" \
      -H "Content-Type: application/json" \
      -d '{
        "contents": [{"role": "user", "parts": [{"text": "A cute orange cat in a garden, photo quality"}]}],
        "generationConfig": {
          "responseModalities": ["IMAGE"],
          "imageConfig": {"aspectRatio": "16:9", "imageSize": "2K"}
        }
      }'
    ```
  </Tab>

  <Tab title="Chat Completions">
    ```bash theme={null}
    curl -X POST "https://api.gravitex.ai/v1/chat/completions" \
      -H "Authorization: Bearer sk-xxxxxxxxxx" \
      -H "Content-Type: application/json" \
      -d '{
        "model": "gemini-2.5-flash-image",
        "messages": [{"role": "user", "content": "Generate a cyberpunk city at night"}]
      }'
    ```
  </Tab>
</Tabs>

See [Gemini native format](/en/api-reference/endpoint/gemini-native) and [Nano Banana](/en/api-reference/endpoint/nano-banana).