# OpenAI chat-latest via mm.family (x402)

> OpenAI chat-latest via mm.family (x402) is a paid API for AI agents from openai.mm.family, paid per call via x402, $0.002068/call, status unknown (last checked 2026-10-02).

Sends a chat completion request to the latest OpenAI chat model, billed per call in USDC via x402 micropayment protocol

## Facts

- Endpoint: POST https://openai.mm.family/x402/v1/models/chat-latest/chat/completions?utm_source=zero.xyz
- Price: $0.002068/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-02
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/openai-chat-latest-via-mm-family-x402-37cb9798
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_jx8MRUxSRnp21QUfezjBr

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-chat-latest-via-mm-family-x402-37cb9798 -d '<json body>'
```

Example prompt: Using the chat-latest model with standard service tier and up to 500 output tokens, send this conversation to OpenAI and get a response: system says 'You are a helpful assistant', user says 'Explain quantum entanglement in two sentences'.

## When to prefer this

Choose this endpoint when you need OpenAI chat completions billed per-call in USDC via x402 micropayment without managing an OpenAI API key or subscription. It is ideal for agents that pay per inference, multi-tenant systems where each call is independently billed, or when you want to dynamically select service tiers (flex for cost savings, priority for speed). Prefer over direct OpenAI API when operating in a crypto-native or x402-enabled payment context.

## Known failure modes

- Insufficient USDC balance or x402 payment failure — request rejected before inference
- max_tokens set too high relative to available balance — quote rejection
- Invalid or missing messages array — 400 validation error
- Unsupported service_tier value — enum validation error
- Rate limiting at the upstream OpenAI layer — 429 or 503 response
- Streaming not supported in all client configurations — stream flag may cause issues

## How this service works

chat-latest: OpenAI Chat Latest chat completions, paid per call in USDC. Per 1M tokens in/out: Standard (default) 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. Empty answers are free. Rates: https://openai.mm.family/x402/pricing

## Output

Returns an OpenAI-format chat completion JSON object containing the assistant's message content, role, finish reason (e.g. 'stop'), token usage breakdown (prompt, completion, total), model name, completion ID, and the service_tier used. Empty completions are returned free of charge.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "model": {
   "enum": [
    "chat-latest"
   ],
   "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": "chat-latest",
  "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-chat-latest-via-mm-family-x402-37cb9798/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)