# OpenAI GPT-5.4-Nano Chat Completions (x402/USDC)

> OpenAI GPT-5.4-Nano Chat Completions (x402/USDC) is a paid API for AI agents from openai.mm.family, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-02).

Runs GPT-5.4-Nano chat completions via a pay-per-call x402 endpoint billed in USDC, with Flex and Standard pricing tiers and optional reasoning levels.

## Facts

- Endpoint: POST https://openai.mm.family/x402/v1/models/gpt-5.4-nano/chat/completions?utm_source=zero.xyz
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-02
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/openai-gpt-5-4-nano-chat-completions-x402-usdc-7f4bb1f7
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_cvn3LSY8HeuSNImYbTL3L

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 openai-gpt-5-4-nano-chat-completions-x402-usdc-7f4bb1f7 -d '<json body>'
```

Example prompt: Use the gpt-5.4-nano model at medium reasoning level with flex pricing to answer this question: what are the three main causes of the French Revolution? Limit the response to 300 tokens.

## When to prefer this

Choose this endpoint when you need a lightweight, low-cost GPT-model chat completion and want to pay per call in USDC without an OpenAI subscription — especially useful for AI agents operating in crypto-native or x402-enabled payment environments. Prefer over gpt-4o or gpt-5.4 siblings when minimizing cost per call is the priority, and over gpt-5-nano when you specifically need the 5.4 generation. The reasoning level suffixes (none through xhigh) make this ideal when you want fine-grained control over chain-of-thought depth on a nano-scale model.

## Known failure modes

- Insufficient USDC balance causes payment failure and no completion returned
- max_tokens set too low results in truncated or empty responses (empty answers billed as free)
- Invalid model variant string causes 400 error
- messages array missing required role or content fields causes validation error
- Unsupported service_tier value causes rejection
- Network latency or provider outage returns 5xx error

## How this service works

gpt-5.4-nano: OpenAI GPT 5.4 Nano chat completions, paid per call in USDC. Per 1M tokens in/out: Flex (default) 0.1/0.625, Standard 0.2/1.25; pick with service_tier. Plus $0.0005 (Base) or $0.0005 (Solana) per call; the quote charges input plus 10% of max_tokens. Levels: none, low, medium, high, xhigh (model gpt-5.4-nano:<level>). Empty answers are free. Rates: https://openai.mm.family/x402/pricing

## Output

Returns a JSON chat completion object containing the assistant's reply text, token usage breakdown (prompt, completion, total), finish reason, model name, and the service tier that was used (flex or standard).

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "model": {
   "enum": [
    "gpt-5.4-nano",
    "gpt-5.4-nano:none",
    "gpt-5.4-nano:low",
    "gpt-5.4-nano:medium",
    "gpt-5.4-nano:high",
    "gpt-5.4-nano:xhigh"
   ],
   "type": "string"
  },
  "tools": {
   "type": "array"
  },
  "stream": {
   "type": "boolean"
  },
  "messages": {
   "type": "array",
   "items": {
    "type": "object",
    "required": [
     "role",
     "content"
    ],
    "properties": {
     "role": {
      "type": "string"
     },
     "content": {
      "type": "string"
     }
    }
   }
  },
  "max_tokens": {
   "type": "integer"
  },
  "service_tier": {
   "enum": [
    "flex",
    "default",
    "standard",
    "auto",
    "fast",
    "priority"
   ],
   "type": "string"
  },
  "response_format": {
   "type": "object"
  },
  "reasoning_effort": {
   "type": "string"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "id": "chatcmpl-x",
  "model": "gpt-5.4-nano",
  "usage": {
   "total_tokens": 9,
   "prompt_tokens": 8,
   "completion_tokens": 1
  },
  "object": "chat.completion",
  "choices": [
   {
    "index": 0,
    "message": {
     "role": "assistant",
     "content": "Hello",
     "refusal": null
    },
    "finish_reason": "stop"
   }
  ],
  "service_tier": "flex"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/openai-gpt-5-4-nano-chat-completions-x402-usdc-7f4bb1f7/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from openai.mm.family](https://www.zero.xyz/host/openai.mm.family/llms.txt)