Now you can check the balance of your Shanghai Public Transportation Card on your iPhone, with our new app Card Checker for iPhone, iPod touch and iPad.

Card Checker is simple to use, simply enter the serial number of your card which is imprinted on the back. The app will connect to the internet and retrieve your most recent balance.

You only need to enter your card number once – after that, simply launch the app and it will immediately fetch your balance.

One caveat: we use official data from the Shanghai Public Transportation Card site, and there can sometimes be a 24-48 hour delay before changes in your balance are reflected in the app.

Card Checker is a perfect complement to our Explore Shanghai metro map app.

Card Checker is free forever –  download it now from the App Store.