Officially, the Chase Freedom Flex℠ card’s 5 percent cash back categories for Q4 2021 are Walmart and PayPal (on up to $1,500 in purchases, then 1 percent cash back after that, and activation is required). But what if I told you that almost all online purchases could qualify? It’s true, thanks to PayPal Key.

How PayPal Key works

PayPal Key is a 16-digit virtual card number that can be used anywhere Mastercard is accepted. It’s mostly an online play, although technically an in-person business could type in the card number. PayPal is already widely accepted—its most recent annual report boasted 29 million active merchant accounts–but PayPal Key takes this to the next level.

I recently used PayPal Key to pay four businesses that don’t accept PayPal directly: Amazon.com, my utility company, my wife’s cellphone provider and our internet/cable/home phone service supplier. In doing so, I earned 5 percent cash back from my Freedom Flex card rather than 1 percent.

First, I logged into my PayPal account on my computer (you could also use the app) and PayPal Key was advertised front and center. I clicked “See key” to view the 16-digit number, expiration date and security code. You’ll want to record this information. It’s also worth pointing out that only some PayPal customers have access to PayPal Key; it’s a feature that has been rolling out in stages over the past year or so.

Next, I went to the “Banks and cards” section of PayPal’s website and set my Freedom Flex as my preferred source of funds. After that, I entered the PayPal Key number into the four websites where I was shopping. Then, those purchases were charged to my Freedom Flex card using PayPal Key, thereby earning 5 percent cash back even though none of those merchants directly accept PayPal.

Data security benefits

While I used it mostly to maximize the Q4 Freedom Flex category, the main benefit of PayPal Key is data security. This virtual card number conceals your real card number. If someone were to steal your PayPal Key number, it wouldn’t expose the number printed on your actual credit or debit card. That means you wouldn’t have to get a new physical card or update all the accounts where that number has been saved. You would simply need to get a new PayPal Key and update any places where the compromised PayPal Key number was saved.

Some credit card issuers, such as Capital One and Citi, offer virtual card numbers of their own. Apple Card took this concept a step further, making a virtual card number a standard feature rather than an optional add-on. I’m not aware of any banks that offer virtual debit card numbers, however. You could use PayPal Key for this purpose, and you could even link a bank account itself to PayPal Key. I’d argue that it’s even more important to protect your debit card and bank account numbers than your credit card information.

That’s because, if money is stolen from your bank account or a debit card linked to your bank account, that’s your money that’s missing. You should get it back, assuming you report the fraud promptly, but it could take weeks. When a credit card is hacked, you’re not out any real money–it’s just a line of credit. You can get bogus charges taken off your bill before you have to pay them. While anyone could achieve security benefits from PayPal Key, people paying with debit cards and directly from their bank accounts have the most to gain in this area.

The fine print

There are a few additional PayPal Key nuances that you should know about. It’s only available to certain U.S.-based consumers at this point, and foreign transaction fees apply to cross-border and cross-currency transactions. PayPal Key doesn’t work with Apple Pay or Samsung Pay, and it’s only integrated with Google Pay online (this is too bad, because if PayPal Key were more compatible with mobile wallets, it would be a lot easier to use in-person).

The bottom line

Come for the rewards and stay for the security benefits; that’s a good way for Freedom Flex cardholders to view PayPal Key. It’s also worth noting that the Discover it® Cash Back card counted PayPal as one of its Q3 2021 5 percent cash back categories, so those cardholders should file these tips away in case PayPal makes another appearance in 2022 (the same $1,500 quarterly spending limit applies on that card, cardholders still earn 1 percent cash back after that, and activation is also required).

Using PayPal Key to boost your rewards reminds me of online shopping portals because both require an extra step, but it’s not that hard, and you can earn a much higher return in the process. I might not have made $1,500 in “regular” PayPal purchases in Q4 2021, and I don’t tend to shop at Walmart very much, but thanks to PayPal Key, I’ll have no trouble maxing out the Freedom Flex’s 5 percent categories this quarter. That will give me $75 cash back on $1,500 I would have spent anyway.

Have a question about credit cards? Email me at ted.rossman@bankrate.com and I’d be happy to help.