Part-payment checkout and supplier price and stock sync for agency stores

The challenge

A UK design agency building online stores for its clients needed two pieces of functionality that the standard platform didn't provide.

The first was part payment. One client wanted customers to be able to pay part of an order up front and settle the rest later, with both the customer and the store owner able to see what was still owed.

The second came from a fancy-dress retailer that sold products supplied by a wholesaler. Prices and stock levels changed frequently at the wholesaler's end, and keeping them up to date by hand wasn't practical. The agency needed the store to update itself from the wholesaler's product API, ideally before the end of the month.

What we did

• Part-payment module. We built a custom module for OpenCart that records a pending amount against each order alongside the order total, so a customer can pay in instalments.
• Customer transaction history. Customers can see the payments made against each order and what remains outstanding.
• Admin manual transactions. Store administrators can add transactions manually, for example when a balance is settled offline.
• Payment testing. We demonstrated the full flow with a test order through a PayPal sandbox before handing over.
• Supplier API integration. We implemented a product update method that reads the wholesaler's feed and updates each product's VAT-inclusive retail price and stock quantity in the store.
• Scheduled updates and support. The update was built to run automatically on a schedule via cron, and we continued to support the agency in 2013 with feed checks, updates and fixes.

Tech stack

PHP, OpenCart, SimpleXML, PayPal (sandbox), cron