Short on basic supplies, Venezuelans have reverted to ancient shopping habits: bartering whatever they have.

But the tools of the trade are right out of the 21st century: WhatsApp, Facebook and Instagram.

With food and toiletries in ever shorter supply, their smartphones are helping them survive.

"I have diapers, I will exchange them for a kilo of pasta," says a message on one group in the messaging app WhatsApp.

It is one of hundreds on the "Puerta del Bosque Swap Shop," a group of 250 neighbors in Guatire, east of Caracas.

Countless groups like it buzz with messages on various online networks.

"I only have flour. I'll swap it for sanitary napkins," reads one message.

Another says: "My baby has no milk, I need some."