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

x402

OpenAI GPT-4o Chat Completions (x402/USDC) is a paid API for AI agents from openai.mm.family, paid per call via x402, $0.001027/call, status unknown (last checked 2026-10-02).

Runs GPT-4o chat completions via a pay-per-call USDC micropayment gateway, billed on token usage with Standard or Fast service tiers.

Price / call$0.001027

Seller volume →—

Success—

StatusUnknown

How this service works

gpt-4o: OpenAI GPT 4o chat completions, paid per call in USDC. Per 1M tokens in/out: Standard (default) 2.5/10.0, Fast 4.25/17.0; 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 standard OpenAI chat completion JSON object containing the assistant's reply message, role, finish_reason (e.g. 'stop'), token usage breakdown (prompt, completion, total), the model name, and the service_tier used. Choices array contains one or more candidate responses.

Example use cases

On-demand GPT-4o Q&A agent

“Ask GPT-4o: 'Explain the pros and cons of microservices architecture versus monoliths for a startup' — use the Standard tier and cap the response at 800 tokens.”

Structured data extraction from text

“Send this customer feedback to GPT-4o and ask it to return a JSON object with sentiment, topics, and urgency score: 'The checkout process was confusing and took forever, but the product itself is amazing.'”

Agentic tool-calling workflow

“Use GPT-4o with tool calling enabled to help me plan a 3-day travel itinerary for Tokyo — set max_tokens to 1200 and use the Fast service tier so I get the answer quickly.”

Technical details

Endpoint

POSThttps://openai.mm.family/x402/v1/models/gpt-4o/chat/completions?utm_source=zero.xyz

When to prefer

Choose this endpoint when you need GPT-4o quality chat completions without an OpenAI subscription, want to pay per call in USDC via the x402 protocol, or are building a crypto-native or agentic workflow that requires pay-as-you-go LLM access. Prefer the Standard tier for cost efficiency and Fast tier when latency is critical. Use this over raw OpenAI API when you lack API keys or want programmatic USDC billing.

Side effects

Insufficient USDC balance or failed x402 payment — request rejected before processing
max_tokens set too low — response truncated with finish_reason 'length'
Invalid or missing messages array — 400 Bad Request
Rate limits or quota exceeded on the upstream OpenAI API — 429 or 503
Streaming not supported in all client configurations — may require specific handling
Empty or trivial prompts return empty answers at no charge but yield no useful content

Input

Schema · Request body

Field	Type	Description
model	string
tools	array
stream	boolean
messages	array
max_tokens	integer
service_tier	string
response_format	object
reasoning_effort	string

Output

Schema · Response

{
  "type": "json",
  "example": {
    "id": "chatcmpl-x",
    "model": "gpt-4o",
    "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"
  }
}

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