Magento 2 Module Development

Overview

Build custom Magento 2 modules using the module architecture, dependency injection (DI), service contracts (interfaces), plugins (interceptors), observers, and the repository pattern. This skill covers the Magento 2 module skeleton, XML-based configuration, the Object Manager and DI container, custom REST/GraphQL API endpoints, and database schema management with db_schema.xml (declarative schema).

When to Use This Skill

• When building a custom module that adds new functionality to a Magento 2 store
• When extending or overriding core Magento behavior using plugins or preferences
• When creating custom REST API or GraphQL endpoints for headless integrations
• When adding custom database tables with declarative schema
• When implementing admin grids, forms, and system configuration

Core Instructions

1. Create the module skeleton

   Every Magento 2 module lives in app/code/Vendor/Module and requires at minimum two files: