# FarOut Pay-Per-Call LLM Inference (GPT-5.6-Terra) via x402

> FarOut Pay-Per-Call LLM Inference (GPT-5.6-Terra) via x402 is a paid API for AI agents from farouter.tech, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-14).

Runs a chat completion request against GPT-5.6-Terra via a pay-per-call x402 micropayment gateway, billing exactly $0.001 USDC per request on Base or Solana with no API key required.

## Facts

- Endpoint: POST https://farouter.tech/v1/metered/models/gpt-5.6-terra/chat/completions
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/farout-pay-per-call-llm-inference-gpt-5-6-terra-via-x402-21aecee5
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_pV4InLT-N9jMLVGCflV8t

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-gpt-5-6-terra-via-x402-21aecee5 -d '<json body>'
```

Example prompt: Using FarOut's pay-per-call gateway, send a chat message to GPT-5.6-Terra with the system prompt 'You are a concise assistant' and user message 'Summarize the water cycle in two sentences', with a max of 150 output tokens.

## When to prefer this

Choose this endpoint when you need keyless, accountless access to GPT-5.6-Terra specifically, are operating an autonomous agent with a crypto wallet (Base or Solana), want true pay-per-call economics with no monthly commitment, or need a guaranteed no-charge policy on failed requests. Prefer over traditional OpenAI API when there is no API key available, when micropayment billing is required, or when operating in an x402-native environment.

## Known failure modes

- 402 Payment Required — wallet has insufficient USDC balance or x402 payment not attached
- 400 Bad Request — missing required messages array or invalid role enum value
- Model not found — model ID does not match an available metered model
- Token budget exceeded — max_tokens set higher than model limit
- Network timeout — inference latency exceeds gateway timeout
- Streaming error — SSE stream interrupted mid-response

## 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 an OpenAI-compatible JSON response containing the assistant's reply in choices[0].message.content, finish_reason (e.g. 'stop'), and token usage counts (prompt_tokens, completion_tokens). Failed or unpaid requests are never charged.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "model": {
   "type": "string",
   "description": "Model id from GET /v1/metered/models, e.g. glm-5.3. No provider prefix."
  },
  "stream": {
   "type": "boolean",
   "description": "SSE streaming."
  },
  "messages": {
   "type": "array",
   "items": {
    "type": "object",
    "required": [
     "role",
     "content"
    ],
    "properties": {
     "role": {
      "enum": [
       "system",
       "user",
       "assistant",
       "tool"
      ],
      "type": "string"
     },
     "content": {
      "type": "string"
     }
    }
   },
   "description": "Chat messages, [OI]-compatible {role, content}."
  },
  "max_tokens": {
   "type": "integer",
   "description": "Output token budget. Drives the quote directly."
  }
 }
}
```

## 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-gpt-5-6-terra-via-x402-21aecee5/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)