What is an edge case?

An edge case refers to a rare scenario in which a system or product experiences unexpected results, often due to extreme or unique situations that are not typically encountered during regular usage. These cases are significant because they can reveal vulnerabilities or shortcomings in design, leading to issues that might not be apparent during standard testing or usage.

Identifying edge cases is crucial for developers and UX designers because they ensure that a product is robust and can handle outlier conditions gracefully. Rather than being a common occurrence, these situations usually lie on the fringes of user experiences, making them important to anticipate and address to enhance overall user satisfaction and product reliability. In contrast, the other definitions suggest typical scenarios or ideal situations that do not capture the essence of an edge case.