https://manpages.ubuntu.com/manpages/xenial/man3/Business::PayPal::API::ExpressCheckout.3pm.html
Ubuntu Manpage: Business::PayPal::API::ExpressCheckout - PayPal Express Checkout API
PayPal Express Checkout API
ubuntumanpagebusinesspaypalapi
https://packagist.org/packages/juspay/expresscheckout-php-sdk
juspay/expresscheckout-php-sdk - Packagist.org
Express Checkout SDK for PHP allows easy integration with Juspay's EC payments as a service platform
php sdkjuspaypackagist