# OpenAI Multi-Model Chat Completions via mm.family (x402)

> OpenAI Multi-Model Chat Completions via mm.family (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 pay-per-call access to 25+ OpenAI chat models (GPT-4.1 through GPT-6.1-sol, o-series) via the x402 payment protocol, billed in USDC

## Facts

- Endpoint: POST https://openai.mm.family/x402/v1/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-multi-model-chat-completions-via-mm-family-x402-0c56e7c6
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_rx2i21OIDfSWSa7NMTRqU

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-multi-model-chat-completions-via-mm-family-x402-0c56e7c6 -d '<json body>'
```

Example prompt: Send my conversation to gpt-6.1-sol using the standard service tier with a 2000 token limit and tell me what it says: [system: 'You are a helpful assistant.', user: 'Explain quantum entanglement in simple terms.']

## When to prefer this

Choose this endpoint when you need pay-per-call access to OpenAI's latest and most capable models (GPT-6, GPT-5.x, o-series) without managing an OpenAI subscription, and want to pay in USDC via the x402 protocol. It is especially useful for agentic workflows that need on-demand LLM access billed per call, or when you want to experiment across a wide range of model tiers (nano to sol) and pricing tiers (flex/standard/fast) without committing to a fixed plan.

## Known failure modes

- 429 Too Many Requests on flex tier (by design — flex may be throttled)
- 402 Payment Required if USDC payment via x402 is not attached or insufficient
- Invalid model name returns 400 or unknown model error
- max_tokens quota exceeded causes truncated or refused completion
- Empty response returned (billed as free) if model produces no output

## How this service works

gpt-6.1-sol (OpenAI's newest model) and 25 more OpenAI chat models (gpt-6, gpt-5.x, gpt-4.1, gpt-4o, o-series), paid per call in USDC. OpenAI token rates on Flex (half price, may answer 429; default where offered), Standard (service_tier default) or Fast (fast), plus $0.0005 (Base) or $0.0005 (Solana) per call; the quote charges input plus 10% of max_tokens. Empty answers are free. One endpoint per model: /x402/v1/models/<key>/chat/completions. Rates: https://openai.mm.family/x402/pricing

## Output

Returns an OpenAI-compatible chat.completion JSON object including the assistant's message content, model used, finish reason, token usage (prompt, completion, total), and the service_tier that handled the request. Empty responses are not charged.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "model": {
   "enum": [
    "chat-latest",
    "gpt-4.1",
    "gpt-4.1-mini",
    "gpt-4.1-nano",
    "gpt-4o",
    "gpt-4o-mini",
    "gpt-5",
    "gpt-5-mini",
    "gpt-5-nano",
    "gpt-5.1",
    "gpt-5.2",
    "gpt-5.4",
    "gpt-5.4-long",
    "gpt-5.4-mini",
    "gpt-5.4-nano",
    "gpt-5.5",
    "gpt-5.5-long",
    "gpt-5.6-luna",
    "gpt-5.6-luna-long",
    "gpt-5.6-sol",
    "gpt-5.6-sol-long",
    "gpt-5.6-terra",
    "gpt-5.6-terra-long",
    "gpt-6-astra",
    "gpt-6-astra-long",
    "gpt-6-luna",
    "gpt-6-luna-long",
    "gpt-6-sol",
    "gpt-6-sol-long",
    "gpt-6.1-sol",
    "gpt-6.1-sol-long",
    "o1",
    "o3",
    "o3-mini",
    "o4-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-6-sol",
  "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-multi-model-chat-completions-via-mm-family-x402-0c56e7c6/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)