> ## Documentation Index
> Fetch the complete documentation index at: https://developers.fd.xyz/llms.txt
> Use this file to discover all available pages before exploring further.

# Stablecoin Settlement

> How Prism settles payments in stablecoins — instant, final, no chargebacks.

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.

## Why Stablecoins?

|                      | Traditional (Card Rails)   | Prism (Stablecoin Rails)     |
| -------------------- | -------------------------- | ---------------------------- |
| **Settlement speed** | 2–5 business days          | Seconds                      |
| **Chargebacks**      | Possible for months        | Transactions are final       |
| **Fees**             | 2.9% + \$0.30 typical      | Competitive settlement fees  |
| **Currency**         | Fiat, with FX conversion   | USD-denominated stablecoins  |
| **Merchant setup**   | Merchant account required  | Wallet address is sufficient |
| **Machine-native**   | Requires card numbers, PII | Wallet-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.

## Supported Tokens

Prism settles using any ERC-20 token that implements `transferWithAuthorization` ([ERC-3009](https://eips.ethereum.org/EIPS/eip-3009)). This is the standard that lets the wallet sign a payment off-chain and have Prism execute it on-chain.

Tokens currently enabled:

| Token             | Symbol | Peg | Issuer        | Chains                        |
| ----------------- | ------ | --- | ------------- | ----------------------------- |
| First Digital USD | FDUSD  | USD | First Digital | Ethereum, BSC                 |
| USD Coin          | USDC   | USD | Circle        | Ethereum, Base, BSC, Arbitrum |

<Note>
  In x402 payment requirements, the `asset` field is the token's **ERC-20 contract address** — not the symbol shown above. See the [API Reference](/prism/api-reference/endpoints) for example values.
</Note>

<Tip>
  **FDUSD** is the native stablecoin of the Finance District ecosystem. Merchants settling in FDUSD benefit from tighter integration with FD infrastructure and priority support.
</Tip>

If you need a token that supports ERC-3009 but isn't listed, [contact us](/overview/resources/support). Adding new tokens is straightforward.

See [Network Support](/prism/production/network-support) for the full chain and token compatibility matrix.

## How Settlement Works

<Steps>
  <Step title="Payment Initiated">
    An AI agent's wallet holds stablecoins. The agent initiates a payment via
    a commerce protocol (x402, UCP) by submitting a signed payment
    with the request.
  </Step>

  <Step title="On-Chain Transfer">
    The Spectrum settlement layer executes the stablecoin transfer from the
    agent's wallet to the merchant's wallet on-chain.
  </Step>

  <Step title="Verification">
    Spectrum verifies the on-chain transaction: correct amount, correct token,
    correct recipient, transaction confirmed on the blockchain.
  </Step>

  <Step title="Confirmation">
    Prism confirms the payment to the SDK middleware, which allows the original
    request to proceed.
  </Step>

  <Step title="Webhook Notification">
    Prism delivers a webhook to the merchant's configured endpoint with full
    transaction details — amount, token, chain, transaction hash, and timestamp.
  </Step>
</Steps>

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.

## Settlement on Different Chains

Settlement happens on the chain specified in the payment requirements. Merchants configure their preferred chain(s) in the [Prism Console](https://apps.fd.xyz/prism/), and the payment response tells the agent which chain to pay on. Prism can settle on any EVM-compatible chain. Adding a new network is a contract deployment on our side.

Enabled chains:

| Chain    | Settlement Time | Gas Cost |
| -------- | --------------- | -------- |
| Base     | \~2 seconds     | Very low |
| Arbitrum | \~2 seconds     | Very low |
| BSC      | \~3 seconds     | Low      |
| Ethereum | \~12 seconds    | Higher   |

Need a chain that isn't listed? [Let us know](/overview/resources/support).

**Chain selection guidance:**

* Accept payments on multiple chains for maximum compatibility with different agent wallets
* Consider your agents' chain preferences — settlement is simplest when both sides use the same chain
* L2 chains generally offer faster settlement and lower gas costs

<Tip>
  Test your integration on production with small amounts. The settlement flow
  works identically regardless of transaction size.
</Tip>

## Merchant Payouts

Once stablecoins settle to the merchant's wallet, they're yours. Options include:

* **Hold stablecoins** — Keep the USD-denominated balance as-is
* **Transfer** — Move funds to another wallet or treasury address
* **Re-invest** — Use stablecoins in DeFi or other on-chain activity

The [Prism Console](https://apps.fd.xyz/prism/) shows settlement history, balances by chain, and transaction details for reconciliation.