FALL RIVER, Mass. >> Thousands of people showed up today for a chance to pack and ship products to Amazon customers, as the e-commerce company held a giant job fair at nearly a dozen U.S. warehouses.

Although the wages offered will make it hard for some to make ends meet, many of the candidates were excited by the prospect of health insurance and other benefits, as well as advancement opportunities.

It’s common for Amazon to ramp up its shipping center staff in August to prepare for holiday shopping. But the magnitude of its current hiring spree underscores Amazon’s growth when traditional retailers are closing stores — and blaming Amazon for a shift to buying goods online.

Amazon said it received “a record-breaking 20,000 applications” and hired thousands of people on the spot, and will hire more in the coming days. The number was less than the 50,000 it had announced it was planning to hire before the event took place.

Most of the jobs are full-time positions in packing, sorting and shipping and will count toward Amazon’s previously announced goal of adding 100,000 full-time workers by the middle of next year.

The bad news is that more people are likely to lose jobs in stores than get jobs in warehouses, said Anthony Carnevale, director of Georgetown University’s Center on Education and the Workforce.

On the flip side, Amazon’s warehouse jobs provide “decent and competitive” wages and could help build skills.

“Interpersonal team work, problem solving, critical thinking, all that stuff goes on in these warehouses,” Carnevale said. “They’re serious entry-level jobs for a lot of young people, even those who are still making their way through school.”

The company is advertising starting wages that range from $11.50 an hour in Chattanooga, Tennessee, to $13.75 an hour in Kent, Washington, near Amazon’s Seattle headquarters. The $11.50 rate amounts to about $23,920 a year. In Washington state, the current minimum wage is $11.50 but by 2020 will increase to $13.50. By comparison, the warehouse store operator Costco raised its minimum wage for entry-level workers last year from $13 to $13.50 an hour.

Some job candidates Wednesday were looking to supplement other income.

Rodney Huffman, a 27-year-old personal trainer, said the $13-an-hour job in Baltimore would pay enough to help cover bills while he starts his own company.

“I’m looking to do the night shifts and then run my own company during the day,” he said.

At one warehouse — Amazon calls them “fulfillment centers” — in Fall River, Massachusetts, Amazon was looking to hire more than 200 people today, adding to a workforce of about 1,500. Employees there focus on sorting, labeling and shipping what the company calls “non-sortable” items — big products such as shovels, kayaks, surfboards, grills, car seats — and lots of giant diaper boxes. Other warehouses are focused on smaller products.

While Amazon has attracted attention for deploying robots at some of its warehouses, experts said it could take a while before automation begins to seriously bite into its growing labor force.

“When it comes to dexterity, machines aren’t really great at it,” said Jason Roberts, head of technology and analytics for mass recruiter Randstad Sourceright, which is not working with Amazon on its jobs fair. “The picker-packer role is something humans do way better than machines right now.”

Steve King, 47, a job candidate in Fall River with experience running his own business, agreed: “I don’t think robots are up to snuff yet. I think they will be. Hopefully I can get in before the robots get that good and get above the robots in administration or something.”

In recent years, reports have emerged about difficult working conditions at Amazon’s warehouses, including deaths at two Amazon warehouses in 2014. The company also came under fire in 2011 for extreme heat at its warehouses that caused “heat-related injuries” among workers. Amazon said at the time that it took emergency actions during heat waves and subsequently installed cooling systems in its warehouses.

But many of those who showed up today were excited by the prospects of health insurance and other benefits, as well as advancement opportunities.

“I like to be busy, so I know Amazon is busy and they want hard workers,” retired police officer Brian Trice said.

Trice was among those who stood in line in Baltimore on a hot day as Amazon contractors passed out bottles of water. In Fall River, a line snaked out of the warehouse and under an air-conditioned tent. In Kent, Washington, a vendor offered free cups of shaved ice from a truck playing steel-drum music.

Among those lining up in Kent were 18-year-old Javier Costa and his 49-year-old uncle, Manuel Alvarenga. Costa said the warehouse work wasn’t necessarily what he was looking for, but his uncle, a recent immigrant from El Salvador, was looking for whatever he could get.

“He was making $6 an hour in El Salvador; you can imagine what the people below him were making,” Costa said. “It’s a harder life down there. At this point he just needs a job.”

Ron Joslin, 55, said he’s long worked at call centers, most recently making medical appointments for veterans. But he lost that job in April, and since then hasn’t been able to find work — despite the Seattle area’s hot labor market.

“I don’t believe the numbers reflect what’s really happening,” he said, waiting in a line hundreds of people long. “You want to see what’s really happening, go to the unemployment office and see how many people are there and how long they’ve been unemployed.”

His wife, a regular Amazon shopper, told him about the job fair, he said.

“She heard about it on the news and was like, ‘You need to go there.’ I said, ‘It’s going to be 100 degrees.’ She said, ‘You need to go there.’ She’s tired of me being around the house.”

Some left disappointed. Maureen Schell gave up after several hours at the Fall River site, describing it as a publicity stunt and a “drive to get bodies in the door so they can cherry-pick the warehouse staff they want.”

“It looks like they’re looking for young, healthy warehouse staff only,” said Schell, a 57-year-old searching for work that will put more money into her retirement.

Amazon was also holding events at shipping sites in Ohio, Kentucky, Wisconsin, New Jersey, Illinois and Indiana.