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Surplus Intelligence
Marketplace
PaymentsFiat credit

Fiat Onramps

Surplus Intelligence supports fiat-to-USDC wallet funding through buyer dashboard onramps. USDC lands in the buyer's Base wallet, which you then deposit to get spendable USDC credits. Settling straight from a wallet approval is no longer offered: the two ways to spend are prepaid credit and deposited USDC.

Two different things live on this page. An onramp (MoonPay, Peer/ZKP2P, a manual transfer) converts fiat to USDC in your own wallet - you then deposit it to get withdrawable USDC credits. A Stripe card top-up is not an onramp: it credits a balance directly, which is spendable but never withdrawable.

Live Funding Options

  • Card top-up (Stripe) - fund your balance directly with a card via POST /v1/payments/topup; check it with GET /v1/payments/balance
  • Peer / ZKP2P - Venmo, Revolut, Cash App, PayPal, Wise, Zelle
  • MoonPay via Privy - card, Apple Pay, Google Pay
  • Manual Base USDC transfer to the buyer wallet
The fork on this page
Onramp → your own walletMoonPay, Peer/ZKP2P, manual transfer. USDC you custody and can withdraw.
Card top-up → internal ledgerStripe. Spendable credit that can never be withdrawn.
Both start with fiat and end with you able to spend - but only one leaves you holding withdrawable funds.

How It Works

  1. Sign in and open the buyer funding flow.
  2. Either top up your balance with a card via POST /v1/payments/topup (Stripe), choose an onramp, or copy your wallet address for a direct Base USDC transfer.
  3. Fund the wallet with USDC on Base (onramp/transfer paths).
  4. Approve marketplace spend.
  5. Use your Surplus API key or x402-compatible client. Each request is charged to you as it completes; seller earnings accrue per request and are paid out to sellers in batched USDC transfers on Base.

Enterprise Card Billing

For card-funded balances, Stripe top-up (POST /v1/payments/topup) credits your account and GET /v1/payments/balance reports the current balance. Stripe invoice generation is live, with the Stripe processing fee passed through on the invoice. Onramps remain the cheaper route for pure wallet funding, since they deliver Base USDC without a card-processing leg.

Card top-ups may also trigger a 3-D Secure challenge - your bank asking you to confirm the payment. That is expected on this rail; complete the challenge and the top-up proceeds.

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