Cash, card, app. There's a lot of ways to ride the metro or the bus these days. Add to that: Apple Pay. Even though not as many people use it in mainland China as Apple might like (estimated at about 3% of iPhone users — trombone fail noise), its few fans are loyal. If you're among them, but don't know how to link ApplePay and the Shanghai Metro network just yet, this is for you.
When it comes to general money moving, Alibaba and Tencent are far superior. But to use the metro with Alipay isn't as easy as it could be, and you need a separate app (Metro Da Du Hui). Da Du Hui can't even be linked with WeChat, so in 2018 Apple Pay seized its opportunity and partnered up with UnionPay and the Shanghai and Beijing public transport systems, cutting down on the number of apps needed to ride the bus or subway in these cities.
Unfortunately, the partnership with UnionPay means that you will not be able to set this up with an international credit or debit card like VISA, Mastercard or American Express, effectively putting this off limits for tourists and short-term visitors who don't have a Chinese bank account.