NEW YORK — For decades, Walmart has attracted attention, and taken heat, for how it treats its workforce, including paying low wages and creating unpredictable schedules.

Now, the giant retailer is teaming up with Silicon Valley to try to ease some of its workers’ financial strain. This week, the nation’s largest private employer will begin providing its more than 1.4 million workers a service that will allow them to receive wages before their next payday.

Instead of waiting two weeks between paychecks, Walmart workers can now use an app to access a portion of wages for hours they have already worked. The goal is to help workers avoid costly payday loans and other debt traps.

“We believe this is the right thing to do, and we are happy to champion it,’’ Judith McKenna, Walmart’s chief operating officer, said in an interview.

But Walmart’s new digital initiative also highlights, albeit unwittingly, the financial struggles of Walmart’s low-wage workforce. Even as the economy strengthens, many retail and service industry workers are not earning enough to make ends meet.

“Their paychecks are too small,’’ said Paul Sonn, general counsel of the National Employment Law Project, an labor advocacy group.

The app, which is called Even, also helps workers manage their finances by pinpointing exactly how much they can safely spend before their next paycheck. Walmart pays a fee on behalf of the workers to the technology firm that runs the app.

The Even app has been used by other employers, but never on such a large scale as Walmart is using it. McKenna said employees who are less stressed about their financial stability “feel more confident and more settled at work.’’

The minimum starting wage at Walmart is $9 an hour, which is $1.75 higher than the federal minimum wage but lower than the starting wage at retailers like Costco, which pays $13 an hour, and Target, which recently raised its entry-level wage to $11 an hour.

The average hourly wage for a full-time Walmart worker is $13.85, while the average hourly wage at Costco is about $24.50.

Every Walmart employee can use Even’s financial planning tool, and obtain eight payments, known as instapays, per year free of charge. For most of the workers, the instapays will be deducted from their next paycheck. The workers can pay extra if they want more than eight instapays.

Alexis Adderley, who works nights in a Walmart distribution center in Fort Pierce, Fla., has started using the Even app as part of a pilot program.

At first she was suspicious, she said, that the app was yet another in a long line of financial products like payday advances and “overdraft protection’’ that end up driving low-income workers deeper into a hole.

But Adderley, the mother of four boys ages 8, 7, 4, and 2, said she had been pleasantly surprised.

The app, which connects to her bank account, calculates how much she pays for housing, food, and phone bills and tracks when she makes big monthly payments. With that data, Even provides Adderley a real-time estimate of how much she can spend in a given day.

She earns $19.25 an hour, more than the average Walmart employee, and works 30 hours a week. But money is still tight, especially since she was forced to leave her home after Hurricane Irma. Earlier this week, the app warned Adderley, 30, that she had only enough money to safely spend $9.08 before her next paycheck.

“I would love to save more,’’ she said.

Walmart executives said they learned about Even after reading a New York Times article about the firm a few years ago. The retailer is also working with another tech firm, PayActiv, which facilitates some of the payments.

These partnerships reflect Walmart’s broader effort to make inroads in Silicon Valley, where the old-line retailer is seeking to acquire talent and ideas to boost its digital heft in its battle with Amazon.

Walmart pays a small fee to Even to allow workers to withdraw their wages ahead of payday. Workers can take out only a portion of wages that they have already earned during the two-week pay cycle — so technically, Even says, these are not loans.

“You have earned this money,’’ said Safwan Shah, founder of PayActiv. “Who decides you should get paid every two weeks?’’

Labor groups say the best investment Walmart could make is not in a new app, but in increasing wages.

“All of these solutions to help people live paycheck to paycheck puts the burden on the worker, not the employer,’’ said Carrie Gleason, who works on issues affecting retail and other low-wage workers at the Center for Popular Democracy, an advocacy group.

Walmart and the fintech firms say cash flow issues are not just a problem for the poor, but affect a broad segment of Americans.