# FarOut – Gemini 3.1 Pro Chat Completions via x402

> FarOut – Gemini 3.1 Pro Chat Completions via x402 is a paid API for AI agents from farouter.tech, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-13).

Run a Gemini 3.1 Pro chat completion request billed per-call in USDC via the x402 protocol, with no API key or account required.

## Facts

- Endpoint: POST https://farouter.tech/v1/metered/models/gemini-3.1-pro/chat/completions
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/farout-gemini-3-1-pro-chat-completions-via-x402-f9b77d38
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_M-FtYC6d2dLSXeOTDes4v

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 farout-gemini-3-1-pro-chat-completions-via-x402-f9b77d38 -d '<json body>'
```

Example prompt: Use Gemini 3.1 Pro through FarOut to answer this question — no API key needed, just pay the $0.001 USDC fee per call: 'What are the top three reasons why neural networks overfit, and how can regularization help?'

## When to prefer this

Choose this endpoint when you need Gemini 3.1 Pro specifically and want pay-per-call billing in USDC with no API key, no account registration, and a guarantee that failed calls are never charged. It is ideal for autonomous agents, serverless pipelines, or crypto-native apps that want to pay for AI inference on-demand using Base or Solana. Prefer alternatives if you need streaming responses, fine-tuned models, or usage at a scale where a traditional API subscription would be cheaper.

## Known failure modes

- Payment failure – x402 payment not accepted; call is never charged but returns a 402 error
- Model unavailable – Gemini 3.1 Pro temporarily offline; returns a 5xx error
- Malformed request – missing or invalid messages array; returns a 400 bad request
- Insufficient funds – USDC wallet balance too low to cover the $0.001 fee
- Rate or quota limits – upstream Google quota exhausted; returns a 429 or 503

## How this service works

Pay-per-call LLM inference over x402. Frontier models (GLM, GPT, Gemini, Kimi, DeepSeek, MiniMax) billed per request in USDC on Base or Solana mainnet. No API key, no account. The 402 quotes your exact request; failed calls are never charged.

## Output

Returns a JSON object with an OpenAI-compatible structure: a choices array containing the assistant's reply message (role and content), a finish_reason (e.g. 'stop'), and a usage object with prompt_tokens and completion_tokens counts.

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "usage": {
   "prompt_tokens": 6,
   "completion_tokens": 8
  },
  "choices": [
   {
    "message": {
     "role": "assistant",
     "content": "Hello! How can I help?"
    },
    "finish_reason": "stop"
   }
  ]
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/farout-gemini-3-1-pro-chat-completions-via-x402-f9b77d38/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from farouter.tech](https://www.zero.xyz/host/farouter.tech/llms.txt)