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Overview

Ephemeral Auto-Withdraw onramps create short-lived NGN virtual accounts (25-minute TTL) that convert deposits at a guaranteed rate and automatically settle funds to a specified on-chain address. This is the recommended option for one-time, time-sensitive transactions.

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When to Use

One-time Payments

Single purchases or fixed-amount deposits

Guaranteed Rates

Lock an exchange rate before transferring

Direct Wallet Settlement

Send funds straight to a user’s wallet

Time-sensitive Flows

Transactions that must settle quickly

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Key Characteristics

PropertyValueMeaning
Lifetime25 minutesVirtual account expires after 25 minutes
FX rateLocked to rate_idFirm quote within validity window
ReuseNoVA is never reused
SettlementAuto-withdrawImmediate on-chain settlement
DestinationPer-onrampCan change per transaction
Deposits received after the 25-minute window do not execute automatically and are flagged.

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Settlement Behavior

Converted stablecoins are automatically sent on-chain after FX conversion. Settlement requires specifying:
  • Destination address
  • Asset (USDC or USDT)
  • Blockchain network
{
  "settlement": {
    "mode": "AUTO_WITHDRAW",
    "asset": "USDC",
    "chain": "BASE",
    "destination_address": "0x742d35Cc6634C0532925a3b844Bc9e7595f0bEb"
  }
}
The destination address is not permanent. Each new onramp may specify a different address. See Supported Chains for available networks.

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Deposit Lifecycle (High Level)

  1. User transfers NGN within the 25-minute window
  2. Deposit is received and FX is executed
  3. Withdrawal is broadcast on-chain
  4. Transaction confirms and deposit reaches SETTLED
Typical end-to-end duration is 2–5 minutes, depending on the chain.

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Late Deposit Handling

Deposits are FLAGGED if they:
  • Arrive after the onramp expiry
  • Arrive after the bound rate_id expires
Late deposits do not execute at the locked rate.

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Comparison with Other Types

FeatureAuto-WithdrawMerchant BalancePermanent
Expiry25 minutes25 minutesNever
FX behaviorLockedLockedFloating
SettlementOn-chainBalance creditOn-chain
DestinationPer-onrampDeferredFixed
Best forOne-time paymentsAggregationRecurring

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Limits

  • Per-deposit maximum: $1,000
  • Per-merchant daily limit: $10,000
See Limits & Risk.

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Next Steps

Ephemeral → Merchant Balance

Aggregate deposits before withdrawing

Create Onramp API

Full API reference