# OpenAI GPT-5.4-Mini Chat Completions (x402)

> OpenAI GPT-5.4-Mini 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).

Provides GPT-5.4-Mini chat completions via a pay-per-call x402 API with tiered pricing (Flex/Standard/Fast) and optional reasoning effort levels

## Facts

- Endpoint: POST https://openai.mm.family/x402/v1/models/gpt-5.4-mini/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-mini-chat-completions-x402-efead12c
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_f61Xyw1BtqRAgmxULrY_A

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-mini-chat-completions-x402-efead12c -d '<json body>'
```

Example prompt: Using GPT-5.4-mini on the flex tier with up to 500 output tokens, answer the following: 'What are the top three benefits of using a microservices architecture over a monolith?' Keep the answer concise and structured.

## When to prefer this

Choose this endpoint when you need cost-effective GPT-class text generation with pay-per-call x402 micropayment billing (no subscription), want to select service tiers (Flex, Standard, Fast) to balance cost and latency, or need adjustable reasoning effort levels (none through xhigh). It is ideal for AI agents that need to call OpenAI-compatible chat APIs programmatically without managing API keys or monthly plans, and suits lightweight to medium-complexity tasks where GPT-5.4-mini's capabilities suffice.

## Known failure modes

- Payment failure or insufficient USDC balance returns a 402 Payment Required error
- Invalid model variant name returns a 400 Bad Request
- Exceeding context window for the mini model causes a context length error
- max_tokens set too low may result in truncated or empty responses
- Unsupported service_tier value returns a validation error
- Network timeout on slow inference under the fast tier if load is high

## How this service works

gpt-5.4-mini: OpenAI GPT 5.4 Mini chat completions, paid per call in USDC. Per 1M tokens in/out: Flex (default) 0.375/2.25, Standard 0.75/4.5, Fast 1.5/9.0; 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-mini:<level>). Empty answers are free. Rates: https://openai.mm.family/x402/pricing

## Output

Returns a JSON chat completion object with the assistant's message text, token usage breakdown (prompt, completion, total), finish reason (e.g. 'stop'), model identifier, service tier used, and a unique completion ID. Empty responses (zero-length answers) are billed at no cost.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "model": {
   "enum": [
    "gpt-5.4-mini",
    "gpt-5.4-mini:none",
    "gpt-5.4-mini:low",
    "gpt-5.4-mini:medium",
    "gpt-5.4-mini:high",
    "gpt-5.4-mini: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-mini",
  "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-mini-chat-completions-x402-efead12c/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)