RemitFlex’s Conversions API lets you swap between supported stablecoins or convert stablecoins to fiat in two steps: first request a quote to get a live rate, then execute that quote to lock the rate and settle the conversion. This guide covers both endpoints, explains how quote expiry works, and shows the supported currency pairs.
How conversions work
The conversion flow is always two calls:
- Get a quote — RemitFlex returns a live exchange rate and a
quote_id valid for 30 seconds.
- Execute the quote — You submit the
quote_id; RemitFlex locks the rate and settles the conversion immediately.
This two-step design lets you display an accurate rate to your users before committing funds. Once you execute, the rate is locked regardless of any market movement that occurs during settlement.
Supported conversion pairs
| From | To | Direction |
|---|
USDC | USDT | Stablecoin swap |
USDT | USDC | Stablecoin swap |
USDC | EURC | Stablecoin swap |
EURC | USDC | Stablecoin swap |
USDC | USD | Off-ramp |
USDT | USD | Off-ramp |
EURC | EUR | Off-ramp |
Off-ramp conversions (stablecoin → fiat) settle to a bank account. If you need to deliver fiat directly to a recipient, use the off-ramp guide instead, which combines conversion and bank transfer into a single flow.
Step 1: Get a quote
Call POST /conversions/quote with the source currency, target currency, and amount you want to convert.
curl -X POST https://api.remitflex.com/v1/conversions/quote \
-H "Authorization: Bearer YOUR_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"from_currency": "USDC",
"to_currency": "EURC",
"amount": 5000
}'
{
"quote_id": "qt_01HX9M2P4KZBN8VXQR7YWT3CD",
"from_currency": "USDC",
"to_currency": "EURC",
"amount": 5000,
"converted_amount": 4612.50,
"exchange_rate": 0.9225,
"fee": 12.50,
"fee_currency": "USDC",
"expires_at": "2024-01-15T10:30:30Z",
"created_at": "2024-01-15T10:30:00Z"
}
Quote response fields
| Field | Type | Description |
|---|
quote_id | string | Unique identifier for this quote; pass to /conversions/execute |
from_currency | string | Source currency as requested |
to_currency | string | Target currency as requested |
amount | number | Source amount as requested |
converted_amount | number | Amount you will receive after fees |
exchange_rate | number | Mid-market rate applied |
fee | number | RemitFlex conversion fee |
fee_currency | string | Currency in which the fee is denominated |
expires_at | string | ISO 8601 timestamp after which the quote is invalid |
created_at | string | ISO 8601 timestamp when the quote was generated |
Quotes expire 30 seconds after created_at. If you submit an execute request after expires_at, the API returns a QUOTE_EXPIRED error and you must request a new quote. Always execute within the same request cycle — avoid storing a quote ID for later use.
Step 2: Execute the conversion
Pass the quote_id to POST /conversions/execute. RemitFlex locks the rate and settles the conversion immediately.
curl -X POST https://api.remitflex.com/v1/conversions/execute \
-H "Authorization: Bearer YOUR_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"quote_id": "qt_01HX9M2P4KZBN8VXQR7YWT3CD"
}'
{
"conversion_id": "con_01HX9M3Q7RVZWP9QJDB6CTYMX",
"status": "completed",
"from_currency": "USDC",
"to_currency": "EURC",
"amount": 5000,
"converted_amount": 4612.50,
"exchange_rate": 0.9225,
"fee": 12.50,
"completed_at": "2024-01-15T10:30:05Z"
}
status of completed confirms that the conversion has settled and the converted balance is available in your wallet.
Rate locking guarantee
Once you call /conversions/execute with a valid quote_id, RemitFlex guarantees the quoted exchange_rate regardless of market movement during settlement. Your converted_amount will match exactly what the quote showed.
If you are building a user-facing exchange UI, fetch a new quote each time the user updates the amount or currency pair, and start a countdown timer from expires_at so users know how long the rate is held.
Handling quote expiry
If execution fails with QUOTE_EXPIRED, fetch a fresh quote and retry immediately:
async function convertWithFreshQuote(fromCurrency, toCurrency, amount) {
// 1. Get a live quote
const quoteRes = await fetch('https://api.remitflex.com/v1/conversions/quote', {
method: 'POST',
headers: {
Authorization: 'Bearer YOUR_API_KEY',
'Content-Type': 'application/json',
},
body: JSON.stringify({ from_currency: fromCurrency, to_currency: toCurrency, amount }),
});
const quote = await quoteRes.json();
// 2. Execute immediately — do not await anything else between these two calls
const execRes = await fetch('https://api.remitflex.com/v1/conversions/execute', {
method: 'POST',
headers: {
Authorization: 'Bearer YOUR_API_KEY',
'Content-Type': 'application/json',
},
body: JSON.stringify({ quote_id: quote.quote_id }),
});
const conversion = await execRes.json();
if (conversion.error === 'QUOTE_EXPIRED') {
// Retry once with a new quote
return convertWithFreshQuote(fromCurrency, toCurrency, amount);
}
return conversion;
}
You will receive a conversion.completed webhook event when the conversion settles. See the webhooks guide to set up event listeners for your conversions. 
