# OpenAI GPT-5.4 Chat Completions (x402)

> OpenAI GPT-5.4 Chat Completions (x402) 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 chat completions with up to 272K input tokens, billed per call in USDC via x402 protocol with configurable service tiers.

## Facts

- Endpoint: POST https://openai.mm.family/x402/v1/models/gpt-5.4/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-chat-completions-x402-01fd86ce
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_BCEtB6iRn5mvBePB48pgb

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-chat-completions-x402-01fd86ce -d '<json body>'
```

Example prompt: Send this conversation to GPT-5.4 using the standard service tier with a max of 1000 output tokens: system says 'You are a helpful assistant', user says 'Explain quantum entanglement in simple terms'.

## When to prefer this

Choose this endpoint when you need GPT-5.4 quality responses (up to 272K input tokens) and want to pay per call in USDC without a traditional OpenAI API subscription. It is ideal for agents that handle variable or unpredictable inference loads, prefer crypto-native billing, or need to run in environments where x402 payment is the available protocol. Use gpt-5.4-long for contexts exceeding 272K tokens. Choose faster/cheaper siblings (gpt-5.4-nano, o4-mini) for cost-sensitive or simpler tasks.

## Known failure modes

- Insufficient USDC balance causes payment failure before generation begins
- Exceeding 272K input token limit results in rejection — use gpt-5.4-long sibling instead
- Invalid model enum value (not in allowed list) returns a 400 error
- max_tokens set too high relative to available funds causes quote rejection
- Empty or malformed messages array returns a validation error
- Rate limits at the underlying OpenAI layer may cause 429 errors
- Streaming mode (stream:true) may not be supported by all x402 proxy clients

## How this service works

gpt-5.4: OpenAI GPT 5.4 (<=272K input tokens) chat completions, paid per call in USDC. Per 1M tokens in/out: Flex (default) 1.25/7.5, Standard 2.5/15.0, Fast 5.0/30.0; 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:<level>). Empty answers are free. Rates: https://openai.mm.family/x402/pricing

## Output

Returns an OpenAI-compatible chat completion JSON object containing the assistant's reply text, role, finish reason (e.g. 'stop'), token usage counts (prompt, completion, total), the model name, the service tier used, and a unique completion ID.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "model": {
   "enum": [
    "gpt-5.4",
    "gpt-5.4:none",
    "gpt-5.4:low",
    "gpt-5.4:medium",
    "gpt-5.4:high",
    "gpt-5.4: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",
  "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-chat-completions-x402-01fd86ce/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)