The Pinduoduo logo is seen on a cushion at the company’s office in Shanghai, China.

A Chinese e-commerce site called Pinduoduo, or PDD, is planning to raise at least $1 billion in a U.S. initial public offering, as it fights for market share against giants including Alibaba Group Holding Ltd.

The Shanghai-based firm saw revenue more than triple to $278 million in 2017, according to its filing to the U.S. Securities and Exchange Commission, under the name Walnut Street Group Holding Limited. Losses rose 55 percent to $79.5 million while transaction volumes reached 141.2 billion yuan.

PDD has become one of the fastest-growing startups in China by creating a sort of Facebook-Groupon mashup, where people spot deals on products such as fruit, clothes or toilet paper, and then recruit friends to buy at a discount. It offers merchandise at up to…