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x402engine Gemini 3.1 Pro LLM Endpoint
x402
x402engine Gemini 3.1 Pro LLM Endpoint is a paid API for AI agents from x402engine.app, paid per call via x402, $0.028883/call, status unknown (last checked 2026-10-12).
Sends a chat completion request to Google Gemini 3.1 Pro via a pay-per-call HTTP 402 micropayment API, returning an OpenAI-compatible response
Price / call$0.028883
Success—
StatusUnknown
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
Returns an OpenAI-compatible JSON object containing the model name ('google/gemini-3.1-pro-preview'), a choices array with the assistant message (role, content, finish_reason), and a top-level content field with the response text. Supports streaming SSE when stream=true.
Example use cases
Multimodal document analysis
“Send this PDF invoice to Gemini 3.1 Pro and ask it to extract the vendor name, total amount, and due date — pay per call with USDC.”
Function-calling agent task
“Have Gemini 3.1 Pro decide which of my defined tools to invoke given this user request: 'What's the weather in Tokyo right now?' — pass the tools array and let it return a tool_call.”
Streaming long-form content generation
“Ask Gemini 3.1 Pro to write a detailed 800-word technical blog post about zero-knowledge proofs, streaming the response back as it's generated.”
Technical details
Endpoint
POSThttps://x402engine.app/api/llm/gemini-3.1-pro?utm_source=zero.xyzWhen to prefer
Choose this endpoint when you need Google Gemini 3.1 Pro specifically — not GPT-4 or Claude — and want to pay only per call without managing API keys or subscriptions. Ideal for agents that need an OpenAI-compatible interface with Gemini's multimodal capabilities (PDF, image, video, audio inputs), function calling, and optional streaming. Prefer this over self-managed Gemini API access when you want crypto micropayment billing (USDC on Base/Solana, USDm on MegaETH) and no upfront commitment.
Side effects
- Payment not settled — HTTP 402 returned if USDC/USDm payment fails or is insufficient
- Invalid messages format — missing required 'messages' array or malformed role values causes validation error
- Model capability mismatch — using unsupported parameters (seed, stop, top_p) for this model variant
- Context length exceeded — very long message arrays or large file inputs may hit token limits
- Streaming failure — SSE stream may drop if network connection is interrupted after payment settlement
- Tool call format error — malformed function definitions in tools array cause rejection
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Output
Schema · Response
{
"type": "json",
"example": {
"model": "google/gemini-3.1-pro-preview",
"choices": [
{
"index": 0,
"message": {
"role": "assistant",
"content": "Hello!"
},
"finish_reason": "stop"
}
],
"content": "Hello!"
}
}Tags
x402
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