WowInvoice: Frontend Engineering for a WooCommerce PDF Invoice Plugin - 3 Case Studies

Quick answer

WowInvoice is a WooCommerce plugin by WPXPO that turns orders into PDF invoices, packing slips, and delivery notes. It's available on WowInvoice on WordPress.org. Mahmudun Nabi Kajal started the WowInvoice repository in January 2026 and has authored 671 of its commits. The codebase has one other main developer, Samin Yaser, with 457 commits, so this is shared work, not a solo project. These three case studies each isolate one decision from that history. They're scoped to Kajal's own commits, and where Samin built the layer a case study extends, it says so.

What WowInvoice is

WowInvoice takes a WooCommerce order and renders it as a branded document. Store owners design each document in a React builder inside the WordPress admin, with a live preview next to a settings panel. A PHP layer prepares the order data and renders the final PDF. The repository was started from a copy of the WowShipping plugin's codebase and then rebuilt into a document generator. Kajal's commits lean toward the builder and templates, and Samin's toward the document service and PDF pipeline. The case studies below cross that line in both directions, which is why each one states its starting point.

The case studies

WooCommerce Credit Notes That Show What Was Actually Refunded →

The anchor piece. In August 2026, I chose a one-class first fix over a multi-week rebuild so credit notes would show the refund instead of the whole order. Each refund is classified into one of ten cases and reconciled to the refunded amount.

Extending One Partial-Payment Layer to Four WooCommerce Deposit Plugins →

The integration piece. Between August and September 2026, I added three deposit plugins to an existing provider layer by reading each plugin's source. I also made every balance or installment order resolve to its parent, so one purchase never gets two invoices.

Linking Shared Template Parts to a Live Preview's Settings Panel →

The interaction piece. In April 2026, I switched shared template parts from a callback prop to forwarded refs. I also lifted the settings accordion's state, so clicking part of the preview opens the matching setting.

FAQ

What is WowInvoice?

WowInvoice is a WooCommerce PDF invoice plugin by WPXPO. It generates invoices, packing slips, and delivery notes from orders, and is listed on WordPress.org as "WowInvoice - PDF Invoices & Packing Slips for WooCommerce".

Who did this work?

I'm a frontend developer at WPXPO and authored 671 of the repository's commits between January and October 2026. Samin Yaser authored 457, and each case study here is scoped to my own commits.

Why are these three stories grouped together?

They aren't one initiative. They're three separate decisions from the same codebase: a scoping call on a correctness bug, an integration across plugins I didn't control, and an API choice for shared components.

Did any of this get removed later?

Yes, and the affected case studies say so. In September 2026, a commit removed the credit-note case builder and the partial-payment layer from the repository's free WordPress.org build, and the repository doesn't show where they went.

On this page