SÃO PAULO, Brazil — Its market value briefly surpassed $1 trillion. It has transformed online shopping. And it has had North American cities holding out billions to deliver its new outposts to their doors.

Expansion south, into the nation where Amazon’s namesake river ends, may prove a little harder.

“Amazon is still kind of irrelevant here,” said Raul Prado, a vendor in the rural town of Guaipava, Brazil, who has relied on online retail sites to build up his business. Less than 1 percent of his sales are through Amazon.

Brazil, home to more than 200 million people and the world’s eighth-largest economy, is in many ways an obvious target for Amazon’s next major expansion. Google and Facebook have done well in Brazil, but their digital services — search, social media and advertising — do not have to overcome the hurdles of selling goods and making deliveries.

As a retail behemoth wading into the market, Amazon has found itself playing catch-up with local rivals that know how to navigate Brazil’s distinct challenges: a complicated tax structure, high import costs and the headache of moving goods across a continent-size country.