The retailers are unleashing tools that use artificial intelligence to replicate the help a salesperson at a store might offer, calculate a shopper's most likely body shape, or use 3D models for a virtual fitting room try-on.
Amazon, which some analysts say would surpass Macy's this year as the largest US clothing seller, is offering some customers an Alexa-powered device that doubles as a selfie- stick machine and a stylist.
Retailers want to reduce the rate of online returns, which can be up to 40 per cent, and thus make customers happier, and more likely to be repeat shoppers.