I have a year-end tax tip for you: Be prepared to prove money you received via PayPal or any other payment app — to split a dinner check or as a cash gift for your wedding — was not business income.

Let me explain.

As of 2022, all third-party payment processors in the United States, including Venmo and Cash App, must report payments of more than $600 a year received for goods and services.

This isn't a new tax — just the IRS trying to catch people who are underreporting gig or self-employment income. Even if you hadn't previously received a Form 1099-K, you were still required to report any taxable income received through these platforms on your tax return.

Before the reporting change, the app companies were required to submit a 1099-K only for transactions totaling more than 200 a calendar year with gross payments exceeding $20,000. Now a single transaction or multiple payments that exceed $600 can trigger a 1099-K. It's harder to avoid having the IRS find out your earnings when there's a digital trail.

You can see how gig workers or any cash-driven business — including a teenager earning extra money babysitting or mowing lawns — getting paid via these apps could fly under the income radar. The reporting requirement was part of the American Rescue Plan Act of 2021, the $1.9 trillion pandemic stimulus package that also amended some sections of the Internal Revenue Code.

But — and this is important — money received through these payment apps from friends and relatives as personal gifts or reimbursements for expenses such as splitting a restaurant meal is not taxable.

If, however, there's a mistake and personal payments get misclassified, the IRS says to sort it out with the app company.

"Those who receive a 1099-K reflecting income they didn't earn should call the issuer," the agency said in a year-end tax tip. "The IRS cannot correct it."

And so begins what I predict could be a hot mess next year when tax season opens if folks incorrectly receive 1099-K forms and then have to prove to the IRS that the money was not, in fact, payment for goods and services.

This is what a bride-to-be from Boston worried about after setting up an online account to receive gifts and cash for her wedding.

She and her fiancé used the website MyRegistry to list the gifts they wanted, such as a Crate & Barrel dual citrus squeezer for $21.95. They also arranged on the site for family and friends to send cash gifts to help with their honeymoon expenses by linking to a PayPal account. (She asked not to be named to protect their privacy.)

However, once the total in cash gifts crossed that $600 reporting threshold, PayPal, which is processing the payments for MyRegistry, asked her for her Social Security number. She became worried that the $100 from a cousin and other cash gifts would be taxed.

And thus started her journey to clarify whether her gifts were taxable.

On sites like PayPal, you should be able to designate whether a payment is a personal or business transaction.

Unsure about the notices she was getting, the Boston bride reached out to the customer service departments for both companies.

"Our company is classifying all transactions as gifts with PayPal," said Nancy Lee, president of MyRegistry.

Lee said the company had heard from several customers concerned that their gifts would be taxed.

"These transactions are gifts," she said. "They are absolutely not taxable."

Payment apps have been notifying customers about the new reporting requirement.

"If a customer receives a 1099-K form, which needs to be corrected, they should contact our customer service, and we can work with them to investigate and, if verified, issue a corrected form," a PayPal spokesperson said in an email. "In this instance, the customer would not receive a 1099-K form."

My advice: Keep good records. Go to irs.gov and read "Steps to Take Now to Get a Jump on Your Taxes." Scroll down to the explanation about the new reporting for payment platforms.

Should you receive an incorrect 1099-K, contact the company immediately to protest. The 1099-K forms must be sent by Jan. 31.

"If unsuccessful, report correctly on your return, including attaching an explanation," IRS spokesman Eric Smith said.

My warning: You do not want to have to attach a statement that requires the IRS to manually review your return. There is still a backlog of tax returns at the IRS.

As for the couple getting married, they stopped accepting cash payments for their wedding.

"I do not have a tax person, but I do really want to make sure I do my taxes accurately," the bride said. "So I think I probably will be trying to get one to resolve this if I do get a 1099. But getting one will cost about as much as the gifts we received for our honeymoon."