Amount & quote

Source crypto is what submit accepts — the token the user is sending, from a resolved transfer plan. Fiat (currently USD) is available from the token’s exchangeRate and from the min / quote hooks.

The demo binds two fields with useDualAmountInput and labels the min from useWalletTransferMinAmount.

useWalletTransferMinAmount

const { minAmount, min, isLoading, error, refetch } =
  useWalletTransferMinAmount(plan)

Options

Option	Meaning
plan	Resolved plan, or null

Returns

Field	Meaning
min	{ crypto, fiat? }. crypto is at least display-dust, then ceiled to display decimals; fiat is ceiled to maxFiatDecimals (default 2)
minAmount	Number(min.crypto) when it is a positive finite number, else null (handy for useDualAmountInput)
isLoading / error / refetch	Fetch state

Idle when plan is null or plan.flow === 'unavailable'.

When min.fiat is missing, convertCryptoToFiatCeil({ amount: min.crypto, exchangeRate: token.exchangeRate }) produces a fiat min.

useDualAmountInput

Shared amount hook from @swapped/connect-sdk/react (also used by Coinbase). Keeps crypto and fiat in sync.

import { useDualAmountInput } from '@swapped/connect-sdk/react'

const {
  amount,
  amountDisplay,
  setAmount,
  setAmountExact,
  amountFiat,
  setAmountFiat,
  touched,
  setTouched,
  onBlur,
  error: amountError,
  isValid,
  isFiatAvailable,
  reset,
} = useDualAmountInput({
  exchangeRate: token.exchangeRate,
  token: token.symbol,
  tokenDecimals: token.decimals,
  minAmount,
  maxAmount: Number(token.displayBalance),
  balanceAmount: Number(token.displayBalance),
  maxAmountMode: 'balance',
  clampToMax: true,
  formatCryptoValue: value => `${value} ${token.symbol}`,
})

Options

Option	Meaning
exchangeRate	Token → fiat rate. null disables fiat
token?	Token symbol (display formatting)
maxDecimals?	Max fraction digits while typing crypto
maxFiatDecimals?	Max fraction digits while typing fiat. Defaults to setFormatDefaults({ maxFiatDecimals }), then 2
firstNonZeroDecimalInput?	Expand dust in the crypto input. Defaults to setFormatDefaults({ firstNonZeroDecimalInput }), then false. Independent of display firstNonZeroDecimal
tokenDecimals	On-chain decimals (fiat → crypto and Max clamp)
minAmount?	Minimum in crypto units
maxAmount?	Spendable ceiling in crypto units
balanceAmount?	Raw balance in crypto units
maxAmountMode?	'balance' (default) or 'spendable'
clampToMax?	Clamp typing to the ceiling. Default false
formatCryptoValue?	Format min / max / balance in error messages
touchedDelay?	ms before blur marks touched. Default 0

Returns

Result	Meaning
amount	Full-precision crypto string — pass this to quote / submit
amountDisplay	Crypto string for the input
setAmount / setAmountFiat	Edit one side; the other updates
setAmountExact	Max button (skips the typing sanitizer)
amountFiat	Fiat string (see maxFiatDecimals)
isFiatAvailable	exchangeRate is usable
error	Blocking validation after touch (below_min, …)
warning	Soft above_spendable in 'balance' mode
isValid	No blocking failure (ignores touched)

amountError.code === 'below_min' is what the demo uses for “Minimum amount is …” on both fields.

Core helpers convertCryptoToFiat, convertFiatToCrypto, validateAmountInput are also on @swapped/connect-sdk. See Amount & quote (Core).

useWalletTransferQuote

const { quote, isFetching, error, refetch } = useWalletTransferQuote({
  plan,
  amount,
  debounceMs: 300,
})

Idle when plan is null, plan.flow === 'unavailable', or amount is empty / invalid (including below the plan min). enabled: false skips fetching entirely.

Options

Option	Meaning
plan	Resolved plan, or null
amount	Source crypto string
enabled?	Skip fetching when false. Default true
debounceMs?	Default 300

Returns

Result	Meaning
quote	WalletTransferQuote or null
isFetching	Quote in flight
error / refetch	Fetch state

quote.amountIn, quote.amountOut, quote.networkFee, quote.protocolFeeFiat, quote.estimatedTimeSeconds — Amount & quote (Core).

Quote is display-only. submit only takes plan and amount.

The demo shows amountOut as “You receive ≈ …”, estimatedTimeSeconds, and networkFee (prefix $ when symbol === 'USD').