Repository and Service Layer: What Do They Do?
When building an app, it’s easy for code to get messy as features grow. That’s why developers use architectural patterns to keep things organized. Two common layers you’ll hear about are the repository and the service (or use case) layer.
A repository is all about data access. It’s the part of your code that knows how to fetch, save, update, or delete data. The key is that the repository hides where the data comes from,maybe it’s a database, maybe it’s an API, maybe it’s just in memory. The rest of your app doesn’t need to care. This makes it easy to swap out data sources later, or to mock data for testing.
The service layer, sometimes called the use case layer, is where your business logic lives. This is the code that defines what your app actually does,things like processing an order, sending an email, or calculating a discount. The service layer calls the repository to get or save data, but it doesn’t worry about how that data is stored. By keeping business rules here, you keep your controllers and views focused on UI, not logic.
For example, imagine an e-commerce app. The repository would handle fetching product data from a database or API. The service layer would handle the logic for placing an order, checking inventory, and applying discounts. This separation makes your app easier to test, maintain, and extend.
In summary, repositories handle data, service layers handle logic. Keeping them separate leads to cleaner, more flexible code that’s ready for whatever changes come next.