Layered architecture

Layered architecture partitions an application into distinct horizontal tiers to isolate core business rules from user interfaces and databases.

This pattern (often called n-tier architecture) organizes software components into stacked horizontal layers: typically presentation, business logic, persistence, and database. By enforcing a strict top-down flow where each layer only communicates with the one directly below it, developers achieve a clean separation of concerns. This isolation makes it straightforward to swap out a frontend framework or run isolated unit tests on business logic without touching the underlying database. It remains the industry standard for traditional enterprise applications and CRUD-heavy systems that require predictable, modular codebases.

https://www.geeksforgeeks.org/software-architectural-patterns-in-system-design/