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

# FX quotes

> How an FX quote locks an exchange rate for a limited time, and how to apply it to a transfer exactly once.

An FX quote locks a rate for converting one currency into another. Request a quote, then pass its `id` as `fx_quote_id` on a transfer to apply that rate. Use quotes for any transfer where the source account currency differs from the transfer currency, including stablecoin on-ramps and off-ramps.

## Lifecycle

| Status | Meaning |
| - | - |
| `active` | The quote can be applied. |
| `used` | A transfer already consumed the quote. |
| `expired` | `expires_at` passed before the quote was used. An expired quote stays retrievable. |

`status` and `valid_for` are computed when you read the quote. `valid_for` counts down in seconds and is `0` once the quote is used or expired.

## Rules that affect your integration

* **A quote is single use.** Applying a used quote returns `409 error_fx_quote_used`. Request a new quote for each transfer.
* **Apply it before it expires.** Read `expires_at` or `valid_for` and create the transfer inside that window. Request a new quote if it lapses.
* **The pair must match the transfer.** A transfer whose currency doesn't match the quote returns `422 error_fx_quote_currency_mismatch`. Set `from_currency` to the account you debit and `to_currency` to the currency being sent.
* **`amount_from` is in the source currency.** Pass it in the smallest unit of `from_currency`.
* **Requesting a quote doesn't move money.** Funds move only when you create the transfer.

## Next steps

* [Cross-currency payouts](https://docs.nuvion.co/guides/cross-currency-payouts.md)
* [Stablecoins](https://docs.nuvion.co/guides/stablecoins.md)
* [FX quotes API reference](https://docs.nuvion.co/api-reference/fx-quotes.md)


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