Onetier

OneTier, or one-tier architecture, is a term used in software engineering to describe a design in which the user interface, business logic, and data management reside in a single tier or layer. In this approach, all components run on the same physical device or software stack, as opposed to multi-tier architectures that distribute responsibilities across multiple servers or layers.

Characteristics commonly include a single process or application that handles presentation, logic, and data access; minimal network communication; and deployment as a desktop program or a standalone mobile app with a local data store. Some definitions also include server-based one-tier deployments where the application and database share a single server.

Advantages of one-tier designs include simplicity, reduced deployment and configuration overhead, and low latency due to the absence of inter-tier calls. They can be easier to develop for small-scale or offline applications and provide a straightforward user experience.

Limitations include limited scalability and resilience, difficulties in maintaining and updating business rules or data schemas across many users, and tight coupling between components. As data and user bases grow, multi-tier or microservices architectures are preferred to separate concerns, enable centralized data management, and scale horizontally.

History and usage: One-tier architectures were common in early standalone applications and some mobile apps with local storage. In modern enterprise software, they are often superseded by tiered or monolithic architectures with clearly separated layers.

See also two-tier architecture, three-tier architecture, monolithic architecture, client-server model.