Deposit checkout with a smoother balance-payment flow

The challenge

A Hong Kong online retailer wanted to let customers reserve products with a deposit and pay the balance later. Its OpenCart store used a custom theme and a third-party extension that lets guests view their orders without an account, so any deposit solution had to fit around both.

After testing our demo store, the retailer chose our partial-payment extension but identified gaps in the balance-payment journey. When a customer returned to pay a balance, the item was simply added to whatever was already in their cart, which could mix a balance payment with new purchases and confuse the order. Guest customers had no way to pay their balance at all, and order emails did not show the deposit details customers needed.

What we did

• Installation and theme fit. We installed vQmod so the extension appeared in the admin panel, then modified the storefront templates so the deposit options displayed correctly in the custom theme.
• Clean balance payments. When a customer adds a balance payment, a yes/no prompt offers to clear other products from the cart. While a balance is pending, new products cannot be added, and in both cases the customer is taken straight to checkout.
• Guest balance payments. We added a pay-balance button to the guest order-view page provided by the third-party extension, so customers without accounts can settle their balance.
• Deposit details in emails. Customer and admin order emails now show the deposit and outstanding balance.
• Fixes after testing. We corrected a case where the balance was not added to the cart after the prompt and fixed the guest pay button action, then confirmed both with the client.

Tech stack

PHP, MySQL, OpenCart 3, vQmod