💱 Wrapper for popular Currency Exchange Rate APIs

A PHP API Wrapper to offer a unified programming interface for popular Currency Rate APIs.

Dont worry about your favorite currency conversion service suddenly shutting down or switching plans on you. Switch away easily, without changing your code.

Inspiration 💅

I needed a currency conversion API for my travel website but could not find a good PHP package. The idea of the Rackbeat/php-currency-api package came closest but unfortunately it was just a stub and not implemented.

Features 🌈

Support for multiple different APIs through the use of drivers
A fluent interface to make retrieving exchange rates convenient and fast
Consistent return interface that is independent of the driver being used
Calculations can be made based on the returned data

Supported APIs 🌐

Service	Identifier
FixerIO	`fixerio`
CurrencyLayer	`currencylayer`
Open Exchange Rates	`openexchangerates`
Exchange Rates API	`exchangeratesapi`

If you want to see more services added, feel free to open an issue!

Prerequisites 📚

PHP 8.x or PHP 7.3+ or higher (tested on both 7.3 and 7.4)
The composer dependency manager for PHP
An account with one or more of the API providers listed above

Installation 🚀

Simply require the package using composer and you're good to go!

$ composer require otherguy/php-currency-api

Usage 🛠

Currency Symbol Helper

The Otherguy\Currency\Symbol class provides constants for each supported currency.

！Note: You are not required to use Otherguy\Currency\Symbol to specify symbols. It's simply a convenience helper and does not need to be used. You can simply pass strings like 'USD', 'EUR', ... to all methods.

// 'USD'
$symbol = Otherguy\Currency\Symbol::USD;

Use the all() method to retrieve an array of all currency symbols:

// [ 'AED', 'AFN', ... 'ZWL' ]
$symbols = Otherguy\Currency\Symbol::all();

The names() method returns an associative array with currency names instead:

// [ 'AED' => 'United Arab Emirates Dirham', 'AFN' => 'Afghan Afghani', ... ]
$symbols = Otherguy\Currency\Symbol::names();

To get the name of a single currency, use the name() method:

// 'United States Dollar'
$symbols = Otherguy\Currency\Symbol::name(Otherguy\Currency\Symbol::USD);

Initialize API Instance

$currency = Otherguy\Currency\DriverFactory::make('fixerio'); // driver identifier from supported drivers.

To get a list of supported drivers, use the getDrivers() method:

// [ 'mock', 'fixerio', 'currencylayer', ... ]
$drivers = Otherguy\Currency\DriverFactory::getDrivers()

Set Access Key

Most API providers require you to sign up and use your issued access key to authenticate against their API. You can specify your access key like so:

$currency->accessKey('your-access-token-goes-here');

Set Configuration Options

To set further configuration options, you can use the config() method. An example is CurrencyLayer's JSON formatting option.

$currency->config('format', '1');

Set Base Currency

You can use either from() or source() to set the base currency. The methods are identical.

！Note: Each driver sets its own default base currency. FixerIO uses EUR as base currency while CurrencyLayer uses USD.

Most services only allow you to change the base currency in their paid plans. The driver will throw a Otherguy\Currency\Exceptions\ApiException if your current plan does not allow changing the base currency.

$currency->source(Otherguy\Currency\Symbol::USD);
$currency->from(Otherguy\Currency\Symbol::USD);

Set Return Currencies

You can use either to() or symbols() to set the return currencies. The methods are identical. Pass a single currency or an array of currency symbols to either of these methods.

！Note: Pass an empty array to return all currency symbols supported by this driver. This is the default if you don't call the method at all.

$currency->to(Otherguy\Currency\Symbol::BTC);
$currency->symbols([Otherguy\Currency\Symbol::BTC, Otherguy\Currency\Symbol::EUR, Otherguy\Currency\Symbol::USD]);

Latest Rates

This retrieves the most recent exchange rates and returns a ConversionResult object.

$currency->get(); // Get latest rates for selected symbols, using set base currency
$currency->get('DKK');  // Get latest rates for selected symbols, using DKK as base currency

Historical Rates

To retrieve historical exchange rates, use the historical() method. Note that you need to specify a date either as a method parameter or by using the date() methods. See Fluent Interface for more information.

$currency->date('2010-01-01')->historical();
$currency->historical('2018-07-01');

Convert Amount

Use the convert() method to convert amounts between currencies.

！Note: Most API providers don't allow access to this method using your free account. You can still use the Latest Rates or Historical Rates endpoints and perform calculations or conversions on the ConversionResult object.

$currency->convert(10.00, 'USD', 'THB'); // Convert 10 USD to THB
$currency->convert(122.50, 'NPR', 'EUR', '2019-01-01'); // Convert 122.50 NPR to EUR using the rates from January 1st, 2019

Fluent Interface

Most methods can be used with a fluent interface, allowing you to chain method calls for more readable code:

// Namespaces are omitted for readability!
DriverFactory::make('driver')->from(Symbol::USD)->to(Symbol::EUR)->get();
DriverFactory::make('driver')->from(Symbol::USD)->to(Symbol::NPR)->date('2013-03-02')->historical();
DriverFactory::make('driver')->from(Symbol::USD)->to(Symbol::NPR)->amount(12.10)->convert();

Conversion Result

The get() and historical() endpoints return a ConversionResult object. This object allows you to perform calculations and conversions easily.

！Note: Even though free accounts of most providers do not allow you to change the base currency, you can still use the ConversionResult object to change the base currency later. This might not be as accurate as changing the base currency directly, though.

！Note: To convert between two currencies, you need to request both of them in your initial get() or historical() request. You can not convert between currencies that have not been fetched!

See the following code for some examples of what you can do with the ConversionResult object.

$result = DriverFactory::make('driver')->from(Symbol::USD)->to([Symbol::EUR, Symbol::GBP])->get();

// [ 'USD' => 1.00, 'EUR' => 0.89, 'GBP' => 0.79 ]
$result->all();

// 'USD'
$result->getBaseCurrency();

// '2019-06-11'
$result->getDate();

// 0.89
$result->rate(Symbol::EUR);

// CurrencyException("No conversion result for BTC!");
$result->rate(Symbol::BTC);

// 5.618
$result->convert(5.0, Symbol::EUR, Symbol::USD);

// [ 'USD' => 1.13, 'EUR' => 1.00, 'GBP' => 0.89 ]
$result->setBaseCurrency(Symbol::EUR)->all();

// 1.12
$result->setBaseCurrency(Symbol::GBP)->rate(Symbol::EUR);

Contributing 🚧

Pull Requests are more than welcome! I'm striving for 100% test coverage for this repository so please make sure to add tests for your code.