Amazon has quietly removed the ability to check the balance of an Amazon gift card online.
This had long been the case for Amazon gift cards until March 2016 when they added a ‘Check’ button next the the ‘Apply to your Balance’ button. Today, they removed that option. 🙁
Certainly makes life more difficult, especially for resellers. Might still be possible to balance check by contacting support, but there isn’t any automated option available any longer.