The Subuno PHP SDK by Subuno allows to communicate with the API to implement fraud screening features into applications. It requires cURL dependencies available at http://php.net/manual/en/book.curl.php
Square now has an E-commerce API that brings Square services to third party websites. Square is usually associated with its mobile credit card reader and complementary software. With the E-commerce API, merchants can use their own systems with all the benefit of Square's modern payment services.