# OpenAI GPT-4o Mini Chat Completions (x402/USDC)

> OpenAI GPT-4o Mini 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).

Send a chat conversation to GPT-4o-mini and receive an AI-generated text response, billed per call in USDC via x402 micropayments.

## Facts

- Endpoint: POST https://openai.mm.family/x402/v1/models/gpt-4o-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-4o-mini-chat-completions-x402-usdc-c286d6da
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_5hRf6AFoc5Kx4FG7rDVDO

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-4o-mini-chat-completions-x402-usdc-c286d6da -d '<json body>'
```

Example prompt: Ask GPT-4o-mini to summarize the following article in 3 bullet points using the standard service tier, with a max of 200 output tokens: 'Researchers have discovered a new species of deep-sea fish that can generate its own light using a novel biochemical process...'

## When to prefer this

Choose GPT-4o-mini over GPT-4o when you need low-cost, high-throughput text generation and the task doesn't require advanced reasoning or long context. It is the best fit for classification, summarization, drafting, and extraction tasks where cost per call matters. Prefer this over the standard OpenAI API when you want to pay per call in USDC via x402 without a monthly subscription, or when building agentic pipelines that need autonomous micropayment-based LLM access.

## Known failure modes

- Insufficient USDC balance or x402 payment failure — call returns 402 Payment Required
- max_tokens set too low causing truncated or empty response (empty answers are free)
- Invalid message format (missing role or content fields) — returns 400 Bad Request
- Model overload on fast/priority tier — may return 429 or degrade to slower tier
- Malformed response_format object causing 400 error
- Streaming not supported in all client configurations — stream:true may cause parse errors

## How this service works

gpt-4o-mini: OpenAI GPT 4o Mini chat completions, paid per call in USDC. Per 1M tokens in/out: Standard (default) 0.15/0.6, Fast 0.25/1.0; pick with service_tier. Plus $0.0005 (Base) or $0.0005 (Solana) per call; the quote charges input plus 10% of max_tokens. Empty answers are free. Rates: https://openai.mm.family/x402/pricing

## Output

Returns a JSON object containing the assistant's reply message, the finish reason (e.g. 'stop'), prompt and completion token counts, the model name ('gpt-4o-mini'), and the service_tier used. The choices array holds the generated text under choices[0].message.content.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "model": {
   "enum": [
    "gpt-4o-mini"
   ],
   "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-4o-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": "default"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/openai-gpt-4o-mini-chat-completions-x402-usdc-c286d6da/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)