Every morning after waking up, Hanoi resident Lan checks the Zalo messaging app for what other residents in her roughly 300-unit condominium are selling that day.
Listings vary from fresh produce and meat to boxed lunches and homemade cakes. On one occasion, 10 eggs were going for $2 and a cabbage weighing 1 kilogram for 90 cents.
"You can place an order in the morning and it will be at your door by lunchtime," she said. "It's very convenient."
As a resurgence of the coronavirus keep more Vietnamese consumers at home, Lan is among a growing number of participants on such social media-based marketplaces, where they can buy and sell products with trusted neighbors instead of coming in contact with outsiders.
Hanoi went into lockdown in late July due to the increase in COVID-19 cases, and residents of the Vietnamese capital are still expected to stay home for the most part. The use of ride-hailing apps like Grab is restricted, and physical markets frequently shut down, depending on how the virus is spreading. Many people remain hesitant to leave their homes unless they absolutely must.
Over 200 people are part of Lan's Zalo group. All transactions are conducted online, and most items have no delivery fees. Though prices tend to be higher than at a regular market, Lan said it is reassuring that her condo manager is part of the group and that she already knows the sellers by sight.
"I can place repeat orders without having to worry about any problems," she said.
Ha, another resident of the complex, brings in pork and chicken grown in nearby Bac Giang Province every morning to sell on Zalo. She delivers the meat herself to each door.
Ha is a banker. But now that she is working more often from home, she has been able to earn an extra 5 million dong ($219) a week selling things on Zalo during free time.
"I plan to keep doing this on the side even after the pandemic ends," she said.
Vietnam is believed to have overcome the worst of the delta variant-driven surge. But vaccination rates in the country remain low, and travel restrictions are expected to remain in place for some time.
Sellers on Zalo have grown from relative amateurs to sophisticated merchants amid the protracted curbs, and some now even sell products that are not available at regular markets. With no clear end to the pandemic in sight, community-based online marketplaces are only expected to become a greater fixture in Vietnamese society.