Responses nano (OpenAI · Nano Responses

by Responses nano (OpenAI

POSTBaseSolanaArbitrumPolygonMonadAvalancheeip155:1329OptimismFraxtaleip155:42220stellar:pubnetalgorand:wGHE2Pwdvd7S12BL5FaOP20EGYesN73ktiC1qzkkit8=

$0.003

per call · USD Coin on Base

OpenAI Responses API over x402 - point the OpenAI SDK's responses.create() (or the OpenAI Agents SDK) at base_url https://agent402.tools/v1/nano and pay $0.003 per call in USDC, no API key, no signup. Same models, caps and price as this tier's /chat/completions route; any model here is served through the Responses wire.

Endpoint

POST https://agent402.tools/v1/nano/responses

50

Calls / 30d

1

Unique payers / 30d

Sep 10

Last called

exact

Payment scheme

Call this service

TypeScript · @x402/fetch
import { wrapFetchWithPayment } from "@x402/fetch";
import { privateKeyToAccount } from "viem/accounts";

const account = privateKeyToAccount(process.env.PRIVATE_KEY);
const fetchWithPay = wrapFetchWithPayment(fetch, account);

const res = await fetchWithPay("https://agent402.tools/v1/nano/responses", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({
    "input": "Summarize x402 in one sentence.",
    "max_output_tokens": 128,
    "model": "openai/gpt-5.6-luna"
  }),
});
const data = await res.json();
cURL
curl -X POST \
  "https://agent402.tools/v1/nano/responses" \
  -H "Content-Type: application/json" \
  -d '{"input":"Summarize x402 in one sentence.","max_output_tokens":128,"model":"openai/gpt-5.6-luna"}' \
  -H "X-PAYMENT: <signed x402 payment>"

Example response

{
  "id": "resp_…",
  "model": "openai/gpt-4o-mini",
  "object": "response",
  "output": [
    {
      "content": [
        {
          "annotations": [],
          "text": "x402 is an HTTP-native way for agents to pay per request with USDC.",
          "type": "output_text"
        }
      ],
      "id": "msg_…",
      "role": "assistant",
      "status": "completed",
      "type": "message"
    }
  ],
  "status": "completed",
  "usage": {
    "input_tokens": 14,
    "output_tokens": 18,
    "total_tokens": 32
  }
}

Payment details

Pay to0xabf4fabd7c416fb67202e5f9002389fc75e2a9d0
AssetUSD Coin · 0x833589fcd6edb6e08f4c7c32d4f71b54bda02913
NetworksBase, Solana, Arbitrum, Polygon, Monad, Avalanche, eip155:1329, Optimism, Fraxtal, eip155:42220, stellar:pubnet, algorand:wGHE2Pwdvd7S12BL5FaOP20EGYesN73ktiC1qzkkit8=
Schemesexact, upto

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