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Anton handles four crypto-adjacent flows with the same API surface as fiat:
  • Stablecoin → fiat — you fund in USDC/USDT, beneficiary receives fiat. Anton converts on the way out.
  • Stablecoin → stablecoin — on-chain transfer between wallets.
  • Stablecoin → other crypto — convert and deliver in native crypto.
  • Fiat → stablecoin — fund in fiat, deliver USDC/USDT to a wallet.
The programmatic flow is exactly the same as a fiat payout: create beneficiary → attach wallet instrument → send payout. The differences are in the instrument credentials, the method + network, and the finality model.

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The wallet instrument

A crypto/stablecoin instrument uses method: "crypto" on creation. Credentials are network-specific: 
curl "https://api.antonpayments.dev/v1/beneficiaries/$BEN_ID/instruments" \
  -X POST \
  -H "Authorization: Bearer $ANTON_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: ins-crypto-001" \
  -d '{
    "method": "crypto",
    "currency": "USDC",
    "label": "Primary USDC wallet (Ethereum)",
    "is_default": true,
    "credentials": {
      "wallet_address": "0x742d35Cc6634C0532925a3b844Bc9e7595f0bEb1",
      "network": "ethereum",
      "token_symbol": "USDC"
    }
  }'
network values (see the Payouts — Network enum): ethereum, polygon, arbitrum, optimism, base, avalanche, bsc, tron, solana, bitcoin, lightning, stellar, ripple.

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Memo and tag fields

Some chains require a memo or destination tag to route funds correctly within an exchange:
  • XRP — destination_tag
  • Stellar — memo (text or hash)
  • Cosmos-family — memo
Provide these in credentials when the beneficiary’s receiving address belongs to an exchange. Missing a required tag will send funds to a generic exchange address where they may be unrecoverable.

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Address validation

Anton validates wallet addresses client-side against chain checksums where applicable (EVM chains use EIP-55, Bitcoin uses Base58Check). A malformed address returns 422 invalid_credentials. What Anton does not do: verify the address belongs to the person you intended. There is no equivalent of UK Confirmation of Payee for crypto. The beneficiary PII on the Beneficiary record is for KYC/compliance; on-chain delivery goes to the address you provided, period.

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Sending the payout

Same endpoint as fiat. The method and rail_type distinguish the flow: 
curl https://api.antonpayments.dev/v1/payouts \
  -X POST \
  -H "Authorization: Bearer $ANTON_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: pay-onchain-001" \
  -d '{
    "beneficiary_id": "ben_...",
    "instrument_id": "ins_...",
    "source_amount": "1000.00",
    "source_currency": "USDC",
    "dest_amount": "1000.00",
    "dest_currency": "USDC",
    "method": "stablecoin",
    "rail_type": "stablecoin",
    "fixed_side": "fixed_dest",
    "purpose": "contractor_payment",
    "reference": "INV-2026-04-042"
  }'
For stablecoin → fiat: 
{
  "source_amount": "1000.00",
  "source_currency": "USDC",
  "dest_amount": "920.00",
  "dest_currency": "EUR",
  "method": "sepa",
  "rail_type": "fiat",
  "fixed_side": "fixed_dest"
}
Anton handles the off-ramp — converting USDC → EUR and settling via SEPA — under the hood.

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The finality model

Crypto finality is different from fiat. The processing → sent → completed transitions mean specific on-chain states:
StateOn-chain meaning
processingTransaction broadcast to the network. tx_hash populated.
sentConfirmed in at least one block. block_confirmations >= 1.
completedConfirmations reach required_confirms for the network. Considered final.
failedTransaction rejected at broadcast (invalid nonce, insufficient gas, invalid address). No funds moved.
returnedUncommon — rail operator recovered funds from a chain reversal. Most networks don’t support this.
Required confirmations per network (from the corridor):
  • Bitcoin: 3-6 confirmations (~30-60 min)
  • Ethereum: 12-32 confirmations (~3-6 min)
  • Polygon / Arbitrum / Optimism / Base: network-specific, typically 1-20 minutes to completed
  • Tron: 1-20 blocks (~3-60 sec)
  • Solana: finality at ~1 slot (~400 ms; completed in seconds)
  • Lightning: near-instant
Values populate on the Payout response as block_confirmations and required_confirms progress.

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Gas and network fees

network_fee and network_fee_currency on the Payout record show the on-chain fee. It’s deducted from the settlement, not from your merchant balance — so the dest_amount the beneficiary receives may be smaller than what you intended if the recipient pays fees (depending on method and fee_bearer).

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Refunds and reversals

Crypto is not fiat. There is no chargeback, no reversal-by-default, no UK Faster Payments “return to sender” window. If a payout reaches completed:
  • Funds are on-chain, in the beneficiary’s wallet.
  • Anton cannot recall them. Only the receiving party can return funds by sending a new transaction.
If a payout reaches failed:
  • Nothing moved. Funds are still in your merchant balance (assuming the reserve was released, which Anton does automatically).
If a payout is in processing or sent:
  • Confirmations are in progress. You cannot cancel.

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Gotchas

USDC on Ethereum is not USDC on Tron. Sending USDC-ERC20 to a Tron address loses the funds permanently. Verify the network on the instrument matches what the beneficiary expects BEFORE creating.
Some hardware wallets reject transactions below a dust threshold. Test with a realistic amount in sandbox before shipping a product that supports very small crypto payouts.
Sending to an exchange (Coinbase, Binance, Kraken, etc.) without the required memo or destination tag usually lands in a generic exchange account that requires manual support-ticket recovery. Always capture the memo/tag field when the beneficiary’s wallet is an exchange.
Many tokens use similar names or symbols. Anton validates token_contract where provided. If your credentials include token_contract for a custom ERC-20, Anton will only send that exact contract’s tokens — prevents confused-deputy sends.
On probabilistic-finality chains (Bitcoin, Ethereum before finalization), a transaction that’s sent could theoretically re-org out and move back to processing. Anton’s state model accounts for this — don’t mark the payout as final until completed.

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Stablecoin funding your balance

To pay OUT stablecoin, you first need stablecoin in your merchant balance. Ryan’s integration path: contact support to get a merchant-specific deposit address for each stablecoin/network pair you want to fund in. Deposits are detected on-chain, and once confirmations complete, the balance is credited — fires funding.credit if you’re subscribed. (Programmatic funding address creation is not currently exposed on the merchant API; dashboard-driven for v1.)

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Subscribe to crypto-relevant events

Same payout.* events as fiat — payout.processing, payout.sent, payout.completed, payout.failed. Payload carries tx_hash, network, block_confirmations, required_confirms.

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Next steps

Send a payout

The unified payout API — same shape for fiat and crypto.

FX & exchange

Converting stablecoin to fiat balance for off-ramp payouts.