Round Pay Plus

Everything in Round Pay, Plus Pay Later

Round Pay Plus is Round Pay with two more ways to pay through your Square account: Afterpay (Clearpay in the UK) and Cash App Pay. Cards with 3-D Secure, Google Pay and Apple Pay work just as they do in Round Pay, on the standard checkout and on One Page Checkout.

Afterpay

• Buyers pay in four interest-free installments. Square pays you the full amount, and Afterpay collects from the buyer.
• Afterpay’s own “4 payments of” line under the button, so buyers see the option before they choose.
• Shipping already priced. Afterpay’s window is offered the shipping Zen Cart already worked out, at the same total, and your order keeps the address the buyer gave you.
• Refunds from the order page, full or partial, up to Afterpay’s 120-day limit.
• Afterpay decides which businesses it works with and sets each seller’s smallest and largest order. The button only appears when your store and the order total qualify. An Afterpay sale costs more than a card sale, so check Square’s current pricing first.

Cash App Pay

• On a computer the buyer scans a QR code with their phone and approves in Cash App. The order is placed on the computer.
• On a phone the button opens Cash App, and the buyer comes straight back to your checkout. On the standard checkout their order comments and their agreement to your conditions are kept for that return.
• For US buyers and sellers, in US dollars.

Always the Right Total

On One Page Checkout the total changes when the buyer picks shipping or adds a coupon. Round Pay Plus rebuilds both buttons for the new total, and if the total changes after the buyer approved, nothing is charged and they’re asked to choose again.

Tested End to End

Before release, every payment type was run through Square’s sandbox on a Zen Cart 2.2.2 store, on both checkouts. That covered cards, a 3-D Secure challenge, Afterpay, Cash App Pay by QR code and on a phone, declines, and full and partial refunds.

Moving Up from Round Pay

Install Round Pay Plus in Plugin Manager and it finds the Round Pay you have. It keeps its settings, both sets of credentials and your payment history, backs Round Pay up, checks the copy, and then removes it. Changed your mind? Uninstalling Round Pay Plus puts Round Pay back. Already own Round Pay? The upgrade is $50.

Everything Else from Round Pay

3-D Secure inside the card token, a pinned Square API version, single-use tokens and idempotency keys so nothing is charged twice, real reasons for a decline, refunds, captures and voids from the order page (Zen Cart 2.2.0 and later), a connection check under Modules > Payment, and separate Sandbox and Production credentials. It’s all built on the engine of SquarePay for WHMCS, which has taken live payments since August 2026.

Our Setup Guide Comes with It

The Round Pay guide, plus a page on Afterpay and Cash App Pay. It opens in your account as soon as your order is placed.

Pair It with Fraud Screen

Square’s own checks won’t stop every stolen card, and the chargeback can arrive weeks after you’ve shipped. Our free Fraud Screen plugin scores every order after payment for the signs of stolen-card fraud and holds the risky ones for you to review before anything ships. We recommend it for every store taking cards with Round Pay.

What It Needs

Zen Cart 2.1.0 through 3.0.0 (the order-page tools need 2.2.0 or later), PHP 8.0 through 8.5, HTTPS, and a Square account. Afterpay needs Afterpay’s approval of your business; Cash App Pay needs US dollars. It’s an encapsulated plugin: Plugin Manager installs, upgrades and removes it, and no core file is changed.

Released under the GNU GPL v2: $200 buys the package and one year of updates and support for one store. Renewing is $50 a year and optional; the plugin keeps working either way.

Questions? Contact us; we answer within one business day, usually within a few hours.