What is a horizontal prototype typically used for?

A horizontal prototype is primarily used to explore requirements and designs at a specific level of detail, typically focusing on the user interface rather than the underlying functionality. This type of prototype provides a visual representation of how a system will look and allows stakeholders to assess usability, layout, and interaction without delving deeply into the system's backend processes.

By presenting the interface elements and workflow, a horizontal prototype facilitates early feedback from users and stakeholders, which is crucial for refining requirements and ensuring that the final product meets user needs. This approach allows teams to iterate on designs quickly, emphasize user experience, and identify any potential issues related to usability before significant development takes place.

In contrast, testing backend functionality or creating a fully functioning product relates more to vertical prototypes, which aim to develop complete features but may not encompass the entire user interface at first. Documenting system errors is not the primary goal of a prototype but rather a task associated with testing and quality assurance processes. Thus, the focus on exploring requirements and designs is what makes the horizontal prototype particularly valuable in the early phases of system development.