Domain-driven design (DDD) is a major software design approach,[1] focusing on modeling software to match a domain according to input from that domain's experts.[2] Under domain-driven design, the structure and language of software code (class names, class methods, class variables) should match the business domain. For example, if software processes loan applications, it might have classes like loan application, customer, and methods such as accept offer and withdraw. Domain-driven design is predicated on the following goals: placing the project's primary focus on the core domain and domain logic; basing complex designs on a model of the domain; initiating a creative collaboration between technical and domain experts to iteratively refine a conceptual model that addresses particular domain problems.

In information technology, a service level indicator (SLI) is a measure of the service level provided by a service provider to a customer. SLIs form the basis of service level objectives (SLOs), which in turn form the basis of service level agreements (SLAs);[1] an SLI is thus also called an SLA metric.

A service-level objective (SLO) is a key element of a service-level agreement (SLA) between a service provider and a customer. SLOs are agreed upon as a means of measuring the performance of the Service Provider and are outlined as a way of avoiding disputes between the two parties based on misunderstanding.