This package aims to implement the FTX-US.com REST API endpoints.
You can install the package via composer:
composer require jjpost86/ftxus-php
This library is not hard coupled to Guzzle or any other HTTP library. It follows PSR-18 client abstraction. You'll need to install your own preferred client.
If you want to get started quickly:
composer require jjpost86/ftxus-php php-http/curl-client nyholm/psr7