# x402engine Gemini 3.5 Flash Lite LLM

> x402engine Gemini 3.5 Flash Lite LLM is a paid API for AI agents from x402engine.app, paid per call via x402, $0.00349/call, status unknown (last checked 2026-10-11).

Sends a chat message to Google's Gemini 3.5 Flash Lite model and returns an OpenAI-compatible response, billed per call via USDC micropayment over HTTP 402

## Facts

- Endpoint: POST https://x402engine.app/api/llm/gemini-3.5-flash-lite?utm_source=zero.xyz
- Price: $0.00349/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-11
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402engine-gemini-3-5-flash-lite-llm-f67bd195
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_00SKo3WUcFRhoxQa4NthG

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability x402engine-gemini-3-5-flash-lite-llm-f67bd195 -d '<json body>'
```

Example prompt: Using the pay-per-call Gemini 3.5 Flash Lite endpoint, send this conversation — system: 'You are a helpful assistant', user: 'Summarize the key differences between REST and GraphQL' — and stream back the response.

## When to prefer this

Choose this endpoint when you need a fast, low-cost Google Gemini model with OpenAI-compatible API format and want to pay per call in USDC without a monthly subscription. Ideal for AI agents running intermittent inference tasks, budget-sensitive pipelines, or situations where you need Google's multimodal capabilities (image, video, audio, PDF) without managing API keys. Prefer this over OpenAI GPT models when Gemini's reasoning style or pricing ($0.00349/call) fits better, and over direct Google API access when you want HTTP 402 micropayment billing on Base, MegaETH, or Solana.

## Known failure modes

- Payment not settled — HTTP 402 returned if USDC/USDm payment header is missing or insufficient
- Model does not support requested parameter (seed, stop, top_p) — check /docs/llm-capabilities.md
- Invalid messages array — missing required 'role' field or malformed content
- Tool call schema mismatch — function definition does not conform to required schema
- Streaming not supported in certain client environments — SSE connection drops
- Rate limit or capacity error from underlying Google Gemini API
- Unsupported content type in multimodal messages — image/video/audio URL unreachable

## How this service works

125 production APIs behind HTTP 402 micropayments. 87 LLMs, Kling V3 and Hailuo video generation, image generation, code execution, travel search, web scraping, TTS, and transaction simulation. Pay with USDC on Base, USDm on MegaETH, or USDC on Solana.

## Output

An OpenAI-compatible JSON object containing the model name ('google/gemini-3.5-flash-lite'), a choices array with the assistant message (role, content), finish_reason, and a top-level content field. When streaming is enabled, returns SSE chunks in OpenAI streaming format after HTTP 402 payment settlement.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "bodyType",
    "body",
    "method"
   ],
   "properties": {
    "body": {
     "type": "object",
     "required": [
      "messages"
     ],
     "properties": {
      "seed": {
       "type": "integer",
       "description": "Model-supported seed; see /docs/llm-capabilities.md."
      },
      "stop": {
       "oneOf": [
        {
         "type": "string"
        },
        {
         "type": "array",
         "items": {
          "type": "string"
         },
         "maxItems": 4
        }
       ],
       "description": "Model-supported stop; see /docs/llm-capabilities.md."
      },
      "tools": {
       "type": "array",
       "items": {
        "type": "object",
        "required": [
         "function"
        ],
        "properties": {
         "type": {
          "enum": [
           "function"
          ],
          "type": "string"
         },
         "function": {
          "type": "object",
          "properties": {
           "name": {
            "type": "string"
           },
           "strict": {
            "type": "boolean"
           },
           "parameters": {
            "type": "object"
           },
           "description": {
            "type": "string"
           }
          }
         }
        }
       },
       "description": "Client-executed function definitions; return results using role=tool and tool_call_id."
      },
      "top_p": {
       "type": "number",
       "description": "Model-supported top_p; see /docs/llm-capabilities.md."
      },
      "stream": {
       "type": "boolean",
       "description": "Return live OpenAI-compatible SSE after payment settlement."
      },
      "plugins": {
       "type": "array",
       "items": {
        "type": "object",
        "required": [
         "pdf"
        ],
        "properties": {
         "id": {
          "enum": [
           "file-parser"
          ],
          "type": "string"
         },
         "pdf": {
          "type": "object",
          "properties": {
           "engine": {
            "enum": [
             "native"
            ],
            "type": "string"
           }
          }
         }
        }
       },
       "description": "Optional native PDF parser only; automatically enabled for file inputs."
      },
      "messages": {
       "type": "arra
… (truncated)
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "model": "google/gemini-3.5-flash-lite",
  "choices": [
   {
    "index": 0,
    "message": {
     "role": "assistant",
     "content": "Hello!"
    },
    "finish_reason": "stop"
   }
  ],
  "content": "Hello!"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402engine-gemini-3-5-flash-lite-llm-f67bd195/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402engine.app](https://www.zero.xyz/host/x402engine.app/llms.txt)