The Double Eleven festival was just a 24-hour event on Nov 11 when it was unveiled by Alibaba in 2009, but has stretched into a weekslong shopping spree lasting from mid-October to mid-November this year. Online retailers initiated the promotional event one week earlier this year than previously.

"Consumption has become the main driving force boosting China's economic growth, and the Singles Day shopping carnival is pivotal to unleashing consumers' purchasing potential, bolstering domestic demand and promoting consumption recovery," said Wang Yun, a researcher at the Chinese Academy of Macroeconomic Research.

More stimulus policies are needed to stabilize and expand employment, improve household incomes, and boost people's ability and willingness to spend, so as to further perk up consumption, Wang added.

China's retail sales, a significant indicator of consumption strength, rose 3.3 percent year-on-year in the first three quarters of this year, said the National Bureau of Statistics. Online sales remained a bright spot, rising 8.6 percent year-on-year during the January-September period.

Based on a survey by global consulting firm AlixPartners in early October, consumers still view Singles Day as the most important shopping festival. Most consumers are likely to maintain their spending levels from the previous year, with 25 percent of interviewed shoppers saying that there would be an increase in their overall spending, the consultancy said.

Most of the increased spending based on the survey would be in apparel, daily necessities and cosmetics. Consumers are likely to remain sensible in their spending given the current economic backdrop, it added.

Online retailers have made promotional methods simpler this time, with a key focus on improving user experience and seeking high-quality and long-term growth, as Chinese consumers are more prudent and rational about potential purchases, said Jason Yu, managing director and vice-executive president of CTR Media Convergence Institute.

Yu said retailers hope to roll out new products to attract consumers and build brand image during the shopping spree.

High-quality and intelligent commodities are crucial for stimulating the purchasing appetite of consumers and unleashing new consumption potential, he said.

"A series of pro-consumption policies, such as the consumer goods trade-in program, have played a significant role in bolstering the sales of consumer electronic products and household appliances on major online marketplaces," Yu added.

Meanwhile, Taobao and Tmall have officially integrated JD's logistics during this year's shopping carnival as sellers on these platforms can choose JD Logistics as the delivery method. JD has accepted the mobile payment option from Alipay, which is operated by financial technology company Ant Group.

Industry insiders said these moves signify a key step in breaking down barriers between the two leading internet companies, enhancing interconnectivity of different platforms, and elevating the online shopping experience of users.