Building the Sifero Courier Timeline Plugin

Most plugin tutorials build a plugin that does one thing and has no users. This course does the opposite: it takes a plugin that ships, sells, and runs on other people's stores, and walks through every decision in it. The subject is the Sifero Courier Timeline for WooCommerce plugin, which adds courier companies, order tracking and public shipment status pages to a WooCommerce store.

That choice changes what the lessons can teach. A toy plugin never has to answer the questions this one does. What happens when someone activates it before WooCommerce? Which queries actually run on a store with fifty thousand orders? Where does the capability check go on a screen that three different roles can reach? How do you change a table schema on a site you cannot take offline? Every lesson answers a question the source code had to answer first, and quotes the code that answers it.

The reference material is the official WordPress documentation: the Plugin Handbook, the REST API Handbook, the Internationalization guidelines, the Coding Standards and the Theme Handbook's template-override rules. Where the documentation and the source disagree, the lesson says so and shows what the code does.

You will need the plugin source. It is GPL-licensed, which means you can read it, copy from it, and ship your own version of anything in it. Parts of it are quoted throughout the course under that licence.