You no longer have to trek out to your mailbox to peek at what's inside.

A new program offered by the U.S. Postal Service sends residents free images of their incoming cards and letters via e-mail each day, offering a digital preview hours before the mail carrier rolls down their street.

The free sign-up service, called Informed Delivery, quietly launched nationwide last month. Subscribers receive up to 10 black-and-white snapshots of the front side of letter-sized mail heading for delivery that day, along with a link to view more. The automated images remain available for seven days.

"We know that people are spending a lot of time on their phones and on their devices," said Pete Nowacki, a Minneapolis-based USPS spokesman. "In a way, it brings back that anticipation [factor] of the mail.

"If you're looking for an important piece of mail, it gives you a reason to go in and check to see if something might be coming soon."

The service uses existing technology like bar code readers and optical scanners, which already take pictures of "flat" mail.

Uniting digital technology with hard-copy mail is one way for the industry to remain relevant, he said.

Waiting on a refund check from the IRS? Knowing exactly when it will hit the mail slot might make it easier to rush home and cash it before the banks close.

But after learning about the new service, 33-year-old Matthew Leo said he couldn't imagine a practical use for it.

"The things you actually care about have a tracking number," said Leo of Columbia Heights while lugging a box of CDs he sold on eBay to the downtown Minneapolis post office. "Young people only use the mail when they have to."

Over the past decade, the postal service has recorded a dramatic decline in mail volume.

It handled 61.2 billion pieces of first-class mail in 2016, down from 97.7 billion in 2006 — a 37 percent decrease over 10 years.

Officials hope that Informed Delivery will be another avenue to reach citizens who prefer electronic communications over traditional snail mail.

"It's like opening a different kind of mailbox," said Amber Lenhoff of St. Paul, who signed up for the program earlier this week after receiving a promotional pamphlet.

Lenhoff, 33, described "mail time" as her favorite part of the day because "you never know what you're going to get." As she prepared to depart for a 12-day trip to England, Lenhoff thought it might be handy to keep an eye on what's delivered while she's away.

Although the service wasn't developed with the intent of preventing mail fraud, officials say it certainly serves that function. People who have their mail stolen, for instance, can respond much faster if they know exactly what was intended for delivery that day.

"Whatever is in the e-mail in the morning is in the mailbox in the afternoon," said Robin Chattopadhyay of Roseville, who applauded the system. "It helps me decide if it's worth emptying the mailbox that day."

As for those with disabilities, the preview function offers more independence.

"It's handy to be able to see my mail without asking someone to physically retrieve it," said Mark Siegel of Minneapolis, who has spinal muscular atrophy, a disease that severely limits his mobility.

Testing of the service began in 2014 with the participation of 80,000 postal customers in Virginia; Maryland; Washington, D.C.; New York City, and Connecticut. The service expanded to ZIP codes in all 50 states this spring and will continue to roll out upgrades over the coming weeks.

With limited marketing, many in the Twin Cities have yet to hear about the free service.

But so far, customers appear to be pleased. A USPS survey found that 70 percent of subscribers checked the notifications daily, while 90 percent checked related e-mails at least four days a week.

Informed Delivery is not yet available to customers with post office boxes. While it scans only letter-sized mail now, the service may expand in the future to show address labels of packages as well.

The postal service does not open any of the mail.

Liz Sawyer • 612-673-4648