Square just announced a new service that might make email marketing service providers a little nervous. It’s called Square Marketing, and comes with an email marketing solution for small businesses, who use Square for payments.

It’s unclear exactly how many active merchants Square has under its belt, but according to stats the company released late last year, its merchants make up the 13th largest American retailer. The company told AdAge it has “millions of small businesses” using Square to process transactions. That’s a lot of small businesses who can potentially rely on Square for their email marketing efforts.

Square Marketing is part of a new suite of “customer engagement tools,” which the company says is “uniquely suited for local businesses,” and link online marketing efforts to sales in the real world for those using Square Register.

“You can choose from several beautiful, customizable email templates to create a promotion, an announcement, or an event invitation,” the company explains. “And Square gives you something no one else can offer: preorganized lists of customers who’ve already visited your store — whether loyal, casual, or lapsed — so you can target the right audience with the right message from day one. You might invite loyal customers to a ‘Friends and Family’ event or maybe re-engage lapsed customers with a special deal.”

“More importantly, Square Marketing closes the loop for brick-and-mortar businesses,” it adds. “Traditional email marketing tools show how many people opened your email. But with Square, you see precisely how marketing drives in-store sales, whether customers come back, and how much they spend when they do.”

This all sounds quite attractive for small businesses with physical stores – many of which are still only tip-toeing around online marketing in the first place.

According to the company, the offering caters to a speedy email marketing process, as the templates and distribution lists it builds let you “go from idea to sent email campaign in minutes.”

The Square Dashboard shows results from the email campaigns, including return on investment for each email.

There’s a free version in which you have to pay ten cents per email and one that costs $15 a month for unlimited email and additional features. Here’s a comparison of what you get with each.

Square has been running a pilot test of the service with some sellers. Those who sent out promotions saw open and redemption rates at 2x the industry average, according to the company. One user, who owns a bakery, said she sends out promotions once very two weeks to about 800 customers, and that it’s been a great way to get people into her store.

“Those numbers translate into real dollars,” it says. “Square sellers generated nearly $1,000,000 in sales tied directly to promotion redemptions.”

It says it surveyed its merchants and that 80% of respondents said they’re “very likely” to recommend Square Marketing to colleagues.

Images via Square