BEIJING-- McDonald's Corp. and Yum Brands Inc. are looking to add digital options in China that will make their fast-food sales even faster and win back business after a rough year in the critical Chinese market.

McDonald's will start testing mobile ordering and mobile payment in China under a pilot program in the current third quarter, said a spokeswoman. The aim is to speed payment and meet consumer demands, she said. "Given Chinese consumers being so digital--we are now preparing," she added.

Yum said its KFC business teamed up with technology giant Alibaba Group Holding Ltd. in late June to launch mobile-payment services for 700 of its 4,500-plus stores in China. Customers can pay for their in-store orders of fried chicken in a few seconds by scanning bar codes generated by Alibaba's mobile-payment application Alipay.

Industry consultants say that across the board, Western companies need to experiment more to connect online and in-store business in a market of 885 million mobile users, who employ smartphone apps to book all sorts of real-life services--from hailing taxis to ordering personal chefs to their homes.

Wal-Mart Stores Inc. began using Alipay in some stores in China in May. The industry consultants say mobile payment simplifies the checkout process and reduces the chance a shopper will abandon a purchase.

In recent weeks, McDonald's has also opened digital "Create Your Taste" kiosks at two outlets in Shanghai. At one of the kiosks, 18-year-old Jia Yu tried out building her own burger, choosing from 24 different ingredients on a touch screen. "People always want to try something new, so I just gave it a shot," said Ms. Jia.

Demand for the burgers, which start out at 42 yuan, or around $6.80, has beaten the company's expectations, with purchases of the customizable burgers reaching levels five times higher than McDonald's estimated, the spokeswoman said. The company didn't disclose its estimate.

Attracting more diners and swifter sales is key for both Yum and McDonald's, after Chinese media reports last summer connected the companies with a restaurant supplier that allegedly sold them expired meat. The companies dropped the supplier, but sales suffered and haven't fully recovered.

McDonald's sales at stores open more than a year in China declined 4.8% in the first quarter, said Kevin Ozan, McDonald's chief financial officer, in an April earnings call. The fast-food retailer doesn't disclose total for sales at its China outlets.

Yum said in April that its China sales, which account for roughly half of Yum's revenue, fell 9% to $1.26 billion in its fiscal first quarter that ended in March, down from a year earlier. Those results came after declines in the third and fourth quarters of Yum's previous fiscal year.

Companies want to cater to a growing Chinese trend of consumers who would rather pay with their phones than pull out their wallets, said Forrester analyst Xiaofeng Wang. Many homegrown Chinese chains, like hot-pot restaurant chain Hai Di Lao, which serves meats and vegetables dipped in boiling broth fondue style, are already using mobile payments.

But KFC and McDonald's, should it continue the mobile-payment program after its pilot run, are early entrants to the online-to-offline market compared with their direct rivals, Ms. Wang said.

McDonald's already uses mobile payment in the U.S. and was an early adopter of Apple Inc.'s Apple Pay, which launched last year. But analysts say mobile payment is taking off faster in China because, unlike U.S. consumers, Chinese don't widely use credit cards.

"Convenience is really important. If you don't provide it, your competitor will," Ms. Wang said.

In Shanghai, a young man who gave only his surname, Ge, ordered KFC for the first time using the mobile payment. Mr. Ge was a quick convert, saying he would use his phone again the next time he orders his fried chicken. "It's convenient," he said.

Fanfan Wang in Shanghai contributed to this article.

Write to Laurie Burkitt at laurie.burkitt@wsj.com

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