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Fetch up-to-date FX rates and convert between NGN, USD, USDC, GBP, EUR, KSH, CAD, INR, and RMB.
While KSH (Kenyan Shilling), CAD (Canadian Dollar), INR (Indian Rupee), and RMB (Chinese Yuan) are supported for currency conversion, virtual accounts and deposits are not yet available for these currencies.

Quote FX Rate

Quickly check the converted amount before booking a trade.

Convert Funds

Lock in a quoted rate and move balances between currencies.
1

Get Conversion Quote – GET /conversion/quote

​
from
string
required
Source currency code.
​
to
string
required
Destination currency code.
​
amount
number
required
Amount in the source currency.
curl -X GET "https://api.useonion.xyz/v1/conversion/quote?from=GBP&to=EUR&amount=100" \
  -H "x-api-key: sk_live_…"

{
  "from": "GBP",
  "to": "EUR",
  "amount": 100,
  "result": 116.50
}
​
from
string
required
Source currency.
​
to
string
required
Destination currency.
​
amount
number
required
Requested amount.
​
result
number
required
Converted amount with fees included.
2

Convert Currency – POST /conversion

​
from
string
required
Source currency.
​
to
string
required
Destination currency.
​
amount
number
required
Amount to convert.
​
userId
string
required
Owner of the balance.
curl -X POST "https://api.useonion.xyz/v1/conversion" \
  -H "Content-Type: application/json" \
  -H "x-api-key: sk_live_…" \
  -d '{
    "from": "EUR",
    "to": "USD",
    "amount": 100,
    "userId": "user-123"
  }'

{
  "from": "EUR",
  "to": "USD",
  "amountFrom": 100,
  "amountTo": 108.50,
  "rate": 1.085,
  "id": "uuid-v4"
}
​
amountFrom
number
required
Debited amount.
​
amountTo
number
required
Credited amount.
​
rate
number
required
Final FX rate applied.
​
id
string
required
Conversion reference ID.