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

# FX overview

> Currency exchange and FX tariff management functionality

## Overview

The FX API provides functionality for managing:

* Exchange rate operations
* FX tariffs and fee structures
* Currency conversion
* Rate source management

## Core Concepts

### Exchange Rate Types

* `BUY`: Customer buys target currency
* `SELL`: Customer sells target currency

### Rate Sources

* `european_bank`: European Central Bank rates
* `currency_cloud`: Currency Cloud provider rates

### Fee Calculation Methods

| Method       | Description              | Formula                             |
| ------------ | ------------------------ | ----------------------------------- |
| `fixed`      | Fixed fee amount         | fee = fixed\_fee                    |
| `percentage` | Percentage of amount     | fee = amount \* (percent\_fee/100)  |
| `greater`    | Greater of fixed/percent | fee = max(fixed\_fee, percent\_fee) |
| `lesser`     | Lesser of fixed/percent  | fee = min(fixed\_fee, percent\_fee) |
| `sum`        | Sum of fixed and percent | fee = fixed\_fee + percent\_fee     |

## Validation Rules

### Amount Constraints

* Must be positive number
* Within min/max limits
* Proper decimal places

### Fee Rules

* Valid date range required
* Non-overlapping ranges
* Valid calculation method

## Security Requirements

* Rate updates require elevated access
* Tariff management restricted
* Changes are audited
* Source must be authorized

<Note>
  See individual endpoint documentation for detailed request/response formats and examples.
</Note>