Cash-on-delivery pincode checks for a multi-vendor marketplace

The challenge

An Indian multi-vendor marketplace was running on a popular premium theme with a multi-vendor seller module. Like many Indian stores, it relied on cash on delivery, but not every product could be paid for that way and not every pincode could be served. Customers needed to see clearly whether cash on delivery was available for a product and their location before reaching the payment step.

The difficulty was that the theme replaced the standard checkout with its own quick checkout, and a client-supplied cash-on-delivery extension did not account for it. Any rules had to work in both places, as well as with mixed carts. The seller side also needed attention: the dashboard layout and the buyer-to-seller question link did not match how the marketplace wanted to operate.

What we did

• Seller experience. We reworked the seller dashboard and added an "ask the seller a question" link on product pages.
• Product-level cash on delivery. Each product can show whether cash on delivery is available, with a pincode check button so customers can confirm before adding to cart.
• Quick checkout validation. Using the client's existing cash-on-delivery extension as a base, we added pincode and availability validation inside the theme's quick checkout, and worked through how mixed carts should behave.
• Clean rebuild. At the client's request we set up a fresh OpenCart 1.5.6.4 install with vQmod and the theme, imported the theme data, and carried all custom code across.
• Deployment. We deployed the store to the client's self-managed server, resolving file permission, extraction and session path issues along the way, reviewed changes in a separate demo folder first, and kept backups during the upload.
• Follow-on fixes. A few months later we fixed a bug with seller-side product options and adjusted the logout link to work around the theme's caching.

Tech stack

PHP, MySQL, OpenCart 1.5.6.4, Journal 2 theme, vQmod, Linux VPS