# FarOut GPT-4.5 Chat Completions via x402

> FarOut GPT-4.5 Chat Completions via x402 is a paid API for AI agents from farouter.tech, paid per call via x402, $0.001378/call, status unknown (last checked 2026-09-15).

Runs a GPT-4.5 chat completion request billed per-call in USDC over x402, with no API key or account required

## Facts

- Endpoint: POST https://farouter.tech/v1/metered/models/gpt-5.5/chat/completions
- Price: $0.001378/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/farout-gpt-4-5-chat-completions-via-x402-83bc4d15
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_CiCcbCxsK1ER_REy-cSyV

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-gpt-4-5-chat-completions-via-x402-83bc4d15 -d '<json body>'
```

Example prompt: Using FarOut's pay-per-call gateway, ask GPT-4.5 to explain the difference between Base and Solana in two sentences — bill it to my USDC wallet, no API key needed.

## When to prefer this

Choose this endpoint when you need GPT-4.5 chat completions without an OpenAI API key or account, want true pay-per-call billing in USDC with no subscription, or are building an agent that must operate anonymously or across wallets. Prefer it over standard OpenAI when the x402 payment protocol is already in your stack or when avoiding recurring billing commitments matters.

## Known failure modes

- Insufficient USDC balance — 402 payment required response with exact cost quote before charge
- Invalid or malformed messages array — 400 bad request
- Model identifier not found or unavailable — 404 or 400 error
- Network timeout on inference — no charge applied per failed-call guarantee
- Payment transaction not confirmed on-chain — request rejected without billing

## 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, and a usage object with prompt_tokens and completion_tokens counts — identical in shape to the OpenAI Chat Completions response 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-gpt-4-5-chat-completions-via-x402-83bc4d15/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)