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Stablecoin Settlement

All Prism payments settle in stablecoins on-chain. This is a deliberate design choice: stablecoins give you instant finality, zero chargebacks, and global reach — properties that card rails can’t match, and properties that AI agents need to transact autonomously.

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Why Stablecoins?

Traditional (Card Rails)Prism (Stablecoin Rails)
Settlement speed2–5 business daysSeconds
ChargebacksPossible for monthsTransactions are final
Fees2.9% + $0.30 typicalCompetitive settlement fees
CurrencyFiat, with FX conversionUSD-denominated stablecoins
Merchant setupMerchant account requiredWallet address is sufficient
Machine-nativeRequires card numbers, PIIWallet-to-wallet, no PII
The last point matters most for agentic commerce: AI agents can hold and transact with stablecoins directly. No credit card numbers, no bank accounts, no personally identifiable information. An agent wallet plus stablecoins is the native payment method for machine-to-machine commerce.

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Supported Stablecoins

StablecoinSymbolPegIssuerSupported Chains
USD CoinUSDCUSDCircleEthereum, Base, BSC, Arbitrum
First Digital USDFDUSDUSDFirst DigitalEthereum, BSC
See Network Support for the full chain and token compatibility matrix.

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How Settlement Works

1

Payment Initiated

An AI agent’s wallet holds stablecoins. The agent initiates a payment via the x402 protocol (or ACP/UCP in the future) by submitting a signed payment with the request.
2

On-Chain Transfer

The Spectrum settlement layer executes the stablecoin transfer from the agent’s wallet to the merchant’s wallet on-chain.
3

Verification

Spectrum verifies the on-chain transaction: correct amount, correct token, correct recipient, transaction confirmed on the blockchain.
4

Confirmation

Prism confirms the payment to the SDK middleware, which allows the original request to proceed.
5

Webhook Notification

Prism delivers a webhook to the merchant’s configured endpoint with full transaction details — amount, token, chain, transaction hash, and timestamp.
Settlement is direct wallet-to-wallet. No intermediary holds the funds, no escrow by default. Once confirmed on-chain, the stablecoins are in the merchant’s wallet — available immediately.

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Settlement on Different Chains

Settlement happens on the chain specified in the payment requirements. Merchants configure their preferred chain(s) in the Prism Console, and the 402 response tells the agent which chain to pay on.
ChainSettlement TimeGas CostRecommended For
Base~2 secondsVery lowMost use cases (recommended)
Arbitrum~2 secondsVery lowHigh-frequency payments
BSC~3 secondsLowFDUSD settlement
Ethereum~12 secondsHigherLarge value transactions
Chain selection guidance:
  • Base is recommended for most use cases — fast settlement and minimal gas costs
  • Consider your agents’ chain preferences — settlement is simplest when both sides use the same chain
  • Accept payments on multiple chains for maximum compatibility with different agent wallets
Use testnet chains (Base Sepolia, Ethereum Sepolia, BSC Testnet, Arbitrum Sepolia) during development. Same settlement flow, no real funds required.

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Merchant Payouts

Once stablecoins settle to the merchant’s wallet, they’re yours. Options include:
  • Hold stablecoins — Keep the USD-denominated balance as-is
  • Off-ramp to fiat — Convert to traditional currency via off-ramp services
  • Transfer — Move funds to another wallet or treasury address
  • Re-invest — Use stablecoins in DeFi or other on-chain activity
The Prism Console shows settlement history, balances by chain, and transaction details for reconciliation.