ONE ATOMIC USDC · BASE · X402 V2

The smallest possible nonzero USDC checkout.

Pay exactly one atomic unit of official Base USDC—0.000001 USDC—to prove a real x402 client can authorize, retry, and settle. Browser buyers can optionally prepare the transfer with an injected wallet or pay manually without connecting one. Verified direct buyers receive a permanent, shareable public purchase receipt.

1 atomic USDCPermanent receipt402 Index: healthy

Buy for 0.000001 USDC and get a permanent receipt

Inspect the live one-atomic HTTP 402 →

Open the independent 402 Index verification →

NO X402 CLIENT?Direct Base wallet path

BROWSER CHECKOUT

Pay one atomic unit from any Base wallet.

Create a 30-minute invoice and send exactly 0.000001 official USDC on Base. Use an optional injected wallet for one-click transaction preparation, or pay manually without connecting a wallet. No account, seller signature, private key, or x402 client.

01 · CALL

One stable GET

Request /api/x402-one-atomic without credentials or inputs and receive an HTTP 402 challenge.

02 · AUTHORIZE

One atomic unit

The exact offer requests 1 atomic unit of official six-decimal Base USDC.

03 · RETRY

Identical request

Retry the same URL with PAYMENT-SIGNATURE; no caller input can drift between challenge and retry.

04 · PROVE

Keep the receipt

Successful JSON proves protected delivery; PAYMENT-RESPONSE carries facilitator settlement evidence.

MINIMUM NONZERO USDC

A real mainnet payment, with dust-sized purchase friction.

USDC has six decimals, so one atomic unit is its smallest nonzero representable amount. The result is deterministic and has no post-payment dependency.

{
  "product": "BountyWorth One-Atomic Base x402 Settlement Canary",
  "paid": true,
  "network": "eip155:8453",
  "amountAtomic": "1",
  "amountUsdc": "0.000001",
  "minimumNonzeroUsdc": true,
  "settlementEvidence": "Read PAYMENT-RESPONSE"
}

PERMANENT PUBLIC PROOF

A purchase receipt that remains shareable after the checkout closes.

Every verified direct purchase gets a stable receipt URL keyed by its public Base transaction hash. It records the official USDC contract, exact seller and amount, paid time, invoice ID, and independent explorer link. Reading the receipt is free.

GET /api/x402-one-atomic/receipt?transactionHash=0x…

{
  "paid": true,
  "protocol": "direct-base-usdc",
  "network": "eip155:8453",
  "amountAtomic": "1",
  "transactionHash": "0x…",
  "explorer": "https://base.blockscout.com/tx/0x…"
}

EXACT SCOPE

A settlement canary, not a faucet or refund loop.