The boom in e-commerce and social media in China is leading hundreds of millions of Chinese consumers to pay with their mobile phones. In China, mobile payment volume increased about 165% to 208.41 trillion yuan ($31.37 trillion) in 2016, according to China E-Commerce Research Center, a market research firm.

WeChat, China’s dominant mobile-based social network, has seen explosive growth in its payment business, WeChat Pay. Tencent Holding Ltd., WeChat’s parent and a large Chinese company in internet gaming and social media, says WeChat’s monthly active users grew 19.5% to 962.8 million in 2016. And in the first half of 2017 WeChat’s revenue from its payment business tripled over the same time in the prior year, according to Tencent, although it didn’t provide sales figures.

WeChat’s growth has benefited JD.com, one of China’s e-commerce leaders, which has had an alliance with Tencent since 2014. JD says about 30% of new mobile shoppers come from WeChat.

Besides shopping online, Chinese consumers can conduct a wide variety of transactions from within the WeChat app, including hailing a taxi, booking a table in a restaurant, buying groceries and paying at food stands in the street. 300,000 stores in China accept WeChat Pay. The number of average daily mobile payment transactions on WeChat exceeded 600 million in 2016.

WeChat Pay also has in-store shopping capabilities, with a feature that lets a shopper scan the QR code on a product and pay for it instantly via the app. Consumers also can follow retailers’ accounts on WeChat to see shopping suggestions, access coupons and make purchases in retailers’ WeChat storefronts.

Tencent says having social and payment information connected via its unified user login enables retailers to better understand consumer behavior online and in stores so that they can more effectively present personalized offers.

WeChat Pay’s largest competitor is Alipay, an affiliate of Alibaba Group Holding Ltd., China’s leading e-commerce company. The huge transaction volume Alipay handles on Alibaba’s popular online marketplaces, Taobao and Tmall, makes Alipay the leader in terms of transaction value. However, its market share in online payments in China decreased to 50% in 2016 from 79% two years ago, while Tencent’s share grew to 38% from 8% in the same period, according to data from China E-commerce Research Center.

Alipay says it users reached 450 million in 2016 and about 71% of transactions come from mobile devices.

As more Chinese consumers travel outside of the country, China’s mobile payment operators are following their customers and expanding the number of overseas merchants that accept their brands. Alipay said that more than 120,000 stores in North America, Europe and Asia accept Alipay. Meanwhile, WeChat says it has entered 12 countries. According to Tencent, more than 1,000 merchants in North America accept WeChat Pay, including duty-free retail chain DFS Group Ltd. and Caesars Entertainment Corp., an operator of casinos, hotels and golf courses.