When Ben Mackinnon moved into a new apartment with his fiancee a year and a half ago, he channeled a lot of money into their new place.
"[Moving is] an expensive process," he tells CNBC. "I spent a bunch of money on a new TV, couch, bed, and all these other things."
As he was reviewing his credit card statements, he stumbled upon his bank's online shopping portal, which lets you earn even more rewards points for each dollar spent on purchases at participating stores.
"I was very aware of my category rewards — like two times points on dining and three times points on travel — but I had no idea that other rewards and offers existed, so I decided to see what I missed out on," Mackinnon says. "It was actually really frustrating. I bought a TV at Lowe's and I could have earned $75 cash back if I had just shopped through my bank shopping portal. It was a similar thing with our couch and bed."
In total, he missed out on nearly $400 worth of extra points and cash back during the two-month moving period.
"I figured I should see if it's a problem that everyone else has," Mackinnon tells CNBC.
After surveying about 900 people, he found that 75% of consumers didn't know that they could earn points, miles, and cash back by using their bank shopping portal. "The primary way that card issuers let consumers know about these offers is through email or their banking site, so the offers just get lost in the shuffle," Mackinnon explains.
This is where Mackinnon's new start-up, Kard, comes in. The New York City-based company, which he founded in December 2015, aims to help consumers maximize their credit card rewards programs by making them aware of the best merchant-specific offers when shopping.
"Our users can earn between 7% and 8% on their annual spend," the CEO tells CNBC. "Of course, it depends on how much you're spending, but that could be a couple hundred dollars to over a thousand dollars in extra cash back, miles, and rewards."
To use Kard, you simply install a free Chrome extension, which you can do on Kard's website, and type in the credit cards you use. You don't give any personal information, just the type of card. Then, whenever you're shopping online, Kard will notify you if any offers are available and help you activate the deal.
"With the extension, you'll get a little push notification in the top right-hand corner of your browser that says something like, 'Use your Amex card and get $25 off your $50 purchase,'" Mackinnon explains. "It's very unobtrusive to the user, but provides a lot of value. If you don't want the offer, you can just X out of the notification."
Here's an example of what a Kard notification would look like on your browser:
The value is three-pronged, the CEO says: "Number one, we're making people aware of these offers; two, we're aggregating all of the offers in one place; and three, we're making sure that once you download our extension, you never have to come back to our website.
"It's a 'set-and-forget' type thing. You just tell us which credit cards you have and we make sure that you're aware of the best offers in real time whenever you're shopping."
The four-person Kard team released the product in August 2016. There are now 4,000 users and former Board Chair of Mastercard, Lance Weaver, recently joined Kard's Board of Directors.
Mackinnon, who built the prototype for Kard on weeknights and weekends while working for his previous employer full-time, advises aspiring entrepreneurs to start with a problem they have in their own life: "With Kard, it was a problem that I saw and that I had myself. If I just started to do some market research and tried to find a problem in something else — and didn't have some sort of personal tie to it — I think things would be much harder."
Correction: This story has been updated to reflect that Ben Mackinnon moved into a new apartment with his fiancee.