Rate

Overview

The Rate endpoint returns the exchange rate for a currency pair with your platform fee already applied on top. Use it to show your users what a conversion will cost before they commit to it. The rate is indicative — it does not reserve or lock a quote, and no funds move. Pass exactly one of source_amount or destination_amount; Superbank computes the other side. Endpoints

GET /v0/rates

Object

Attributes

Attribute	Description
`source_currency`	The currency code being converted from.
`destination_currency`	The currency code being converted to.
`mid_market_rate`	Destination units per one source unit, before any fee.
`inverted_mid_market_rate`	The inverse of `mid_market_rate`, for convenience.
`effective_rate`	The all-in rate the recipient actually receives per source unit, after the fee.
`source_amount`	The amount debited in the source currency.
`destination_amount`	The amount credited in the destination currency.
`fee`	The fee applied on top of the exchange rate.
`fee.total`	The total fee for this conversion, denominated in the source currency. This is a single all-in figure.
`fee.currency`	The currency the fee is denominated in (the source currency).

fee.total is the complete cost of the conversion. It equals the gap between what is debited and what would be received at the mid-market rate (source_amount - destination_amount / mid_market_rate), so the difference between mid_market_rate and effective_rate is fully explained by it.

`GET /v0/rates`

Parameters

Query parameter	Description
`source_currency_code`	Required. The currency to convert from, e.g. `USDC`, `USD`.
`source_rail`	Required. The source rail, e.g. `SOLANA`, `ACH`.
`destination_currency_code`	Required. The currency to convert to, e.g. `CAD`, `USDC`.
`destination_rail`	Required. The destination rail, e.g. `LOCAL`, `RTP`.
`destination_country_code`	The ISO 3166-1 alpha-2 country code of the destination. Required when the destination is fiat.
`source_country_code`	The ISO 3166-1 alpha-2 country code of the source. Required when the source is fiat (on-ramp).
`source_amount`	The amount in the source currency. Mutually exclusive with `destination_amount`.
`destination_amount`	The amount in the destination currency. Mutually exclusive with `source_amount`.

At least one leg must be a stablecoin — fiat-to-fiat pairs are not supported. Stablecoin legs use a crypto rail (SOLANA, ETHEREUM, POLYGON, TRON); fiat legs use ACH, RTP, DOMESTIC_WIRE, or LOCAL.

Request

curl --request GET \
    --url 'https://api-sandbox.superbank.co/v0/rates?source_currency_code=USDC&source_rail=SOLANA&destination_currency_code=CAD&destination_rail=LOCAL&destination_country_code=CA&source_amount=1000' \
    --header 'X-Api-Key: YOUR_API_KEY'

Response

{
  "source_currency": "USDC",
  "destination_currency": "CAD",
  "mid_market_rate": 1.3788512205,
  "inverted_mid_market_rate": 0.7252415072,
  "effective_rate": 1.3651,
  "source_amount": 1000,
  "destination_amount": 1365.1,
  "fee": {
    "total": 9.97,
    "currency": "USDC"
  }
}

Errors

Status	When
`400`	Both or neither of `source_amount` / `destination_amount` were provided.
`400`	An unsupported currency, a rail that doesn’t match the currency, or a fiat-to-fiat pair.
`400`	A fiat leg without its country code.
`401`	Missing or invalid API key.

Guides

API Instructions

Core Resources

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Overview

Object

Attributes

`GET /v0/rates`

Parameters

Request

Response

Errors

​Overview

​Object

​Attributes

​GET /v0/rates

​Parameters

​Request

​Response

​Errors

Overview

Object

Attributes

`GET /v0/rates`

Parameters

Request

Response

Errors