> ## Documentation Index
> Fetch the complete documentation index at: https://docs.unleash-commerce.eu/llms.txt
> Use this file to discover all available pages before exploring further.

# Extending Core

> Learn how to extend the Unleash Commerce Core package

## Overview

Unleash Commerce Core is built with extensibility in mind. You can customize nearly every aspect of the core functionality without modifying the package itself.

## Extension Points

The core package provides several ways to extend functionality:

### 1. Contract Binding

Contracts define interfaces for key functionality. You can implement your own versions and bind them in the service container:

```php theme={null}
// In your service provider
$this->app->bind(
    ProductContract::class,
    CustomProductImplementation::class
);
```

### 2. Action Contracts

Actions are the primary way business logic is organized. Each action has a corresponding contract that you can create a custom implementation for.

### 3. Model Extensions

Extend existing models by creating your own subclasses or using observers for additional behavior.

### 4. Manifest System

The core uses manifests to manage mappings between contracts and implementations. This allows swapping implementations without changing code.

## Best Practices

* Always implement the contract interface when creating custom implementations
* Use dependency injection to keep your code loosely coupled
* Test your extensions thoroughly
* Use observers for non-intrusive model behavior

Explore the sections below to learn how to create custom actions and models.