Last December, the financial services giant Paypal finalized a deal that allows the American company to formally enter China’s fast-growing mobile payments market, which is now dominated by home grown behemoths WeChat Pay and Alipay. China had long promised to open up the market to foreign competition, and Paypal became the first foreign firm licensed to provide digital payment services in China by acquiring a 70 percent stake in GoPay, a domestic Chinese payments company with a license to conduct mobile, online, and cross-border payment services.  Now, the company — which trades on the Nasdaq and is valued at close to $150 billion — gets a crack at a market that has been experiencing explosive growth. According to a report by McKinsey, the consulting firm, mobile payment transactions in China grew at an astronomical rate between 2013 and 2018 and reached $600 billion in payments revenue, making it the world leader in digital transactions.  Two other foreign m