OpenAI o3 Chat Completions (x402/USDC)

x402

OpenAI o3 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).

Runs OpenAI o3 reasoning model chat completions, billed per call in USDC via x402 micropayment protocol with configurable reasoning effort and service tiers.

Price / call$0.001

Seller volume →—

Success—

StatusUnknown

How this service works

o3: OpenAI o3 chat completions, paid per call in USDC. Per 1M tokens in/out: Flex (default) 1.0/4.0, Standard 2.0/8.0, Fast 3.5/14.0; pick with service_tier. Plus $0.0005 (Base) or $0.0005 (Solana) per call; the quote charges input plus 10% of max_tokens. Levels: low, medium, high, xhigh (model o3:<level>). Empty answers are free. Rates: https://openai.mm.family/x402/pricing

Output

Returns a JSON chat completion object containing the assistant's reply message, finish reason (e.g. 'stop'), prompt/completion/total token counts, the model used, and the service tier applied. The response mirrors the OpenAI chat completions API format.

Example use cases

Hard coding problem with deep reasoning

“I need o3 at the xhigh reasoning level to debug this recursive Rust function that's producing a stack overflow — here's the code. Keep the answer under 1000 tokens and use flex tier to keep costs down.”

Complex multi-step math derivation

“Can you use o3:high to walk me through the full derivation of the Euler-Lagrange equation from first principles? I want a thorough explanation, up to 2000 tokens, using the standard service tier.”

Agentic tool-use reasoning task

“Run an o3 model completion with medium reasoning effort to decide which of these three investment strategies is most risk-adjusted given the data I'm pasting — keep it under 800 tokens and use fast tier so I get the answer quickly.”

Technical details

Endpoint

POSThttps://openai.mm.family/x402/v1/models/o3/chat/completions?utm_source=zero.xyz

When to prefer

Choose this endpoint when you need OpenAI's o3 reasoning model specifically — particularly for hard math, coding, logic, or multi-step reasoning tasks — and want to pay per call in USDC via the x402 protocol without a traditional API key subscription. Prefer o3:high or o3:xhigh for maximum reasoning depth, o3:low for speed, and flex tier for cost efficiency. Use over alternatives when you need the full o3 reasoning capability (vs o3-mini) or want crypto-native micropayment billing.

Side effects

Insufficient USDC balance — payment rejected before inference runs
max_tokens set too high relative to available credit — quota exceeded
Invalid model variant string — enum validation error
Empty response if query is flagged as policy-violating (returned free of charge)
Timeout on very large completions at flex tier due to deprioritized queue
Malformed messages array (missing role or content) — 422 validation error

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": "o3",
    "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"
  }
}

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