# FarOut Pay-Per-Call LLM Inference via x402 (GPT-5.3-Codex)

> FarOut Pay-Per-Call LLM Inference via x402 (GPT-5.3-Codex) 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).

Runs a GPT-5.3-Codex chat completion request billed per-call in USDC via the x402 payment protocol, with no API key or account required.

## Facts

- Endpoint: POST https://farouter.tech/v1/metered/models/gpt-5.3-codex/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-pay-per-call-llm-inference-via-x402-gpt-5-3-codex-19a1c9d8
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_xiy17a9rwScYkn77njmxR

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-pay-per-call-llm-inference-via-x402-gpt-5-3-codex-19a1c9d8 -d '<json body>'
```

Example prompt: Ask GPT-5.3-Codex through FarOut — paying with USDC from my Base wallet, no account needed — to write me a Python function that parses JSON and handles missing keys gracefully.

## When to prefer this

Choose this endpoint when you need LLM inference without account registration or API key management, want strict pay-per-call billing in USDC to avoid subscription overhead, or are building an agent that must self-fund AI calls via blockchain micropayments. Prefer it over traditional OpenAI direct access when operating in a trustless or anonymous context, or when using x402-compatible payment infrastructure on Base or Solana.

## Known failure modes

- 402 Payment Required if wallet has insufficient USDC balance
- Payment rejected if x402 handshake fails or blockchain confirmation times out
- Model unavailable or rate-limited upstream at the provider level
- Malformed request body (missing 'messages' field) returns 400
- Network timeout if the inference call exceeds latency limits

## 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

A JSON object containing the assistant's reply text under choices[0].message.content, finish_reason (e.g. 'stop'), and a usage object with prompt_tokens and completion_tokens counts. The response mirrors the OpenAI Chat Completions API format.

## 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-pay-per-call-llm-inference-via-x402-gpt-5-3-codex-19a1c9d8/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)