capii

Capii is a term encountered in various online discussions with no universally recognized definition. In many software engineering contexts, capii is used informally as a placeholder acronym for a hypothetical “Common API Interface Initiative”—a proposed framework for designing, versioning, and composing APIs and middleware. Because it is not part of any official standard, interpretations of capii vary between projects; most discussions describe it as a general architectural concept rather than a concrete product.

Etymology and usage notes: The form capii resembles a Latin-derived plural or a stylized project name, and is typically written in lowercase in informal writings. It is not an established acronym within recognized API or software architecture standards, and there is no official governing body or specification.

In practice, when capii is invoked, it is usually to discuss ideas such as standardizing API contracts, promoting loose coupling between services, supporting multi-API orchestration, and enforcing uniform observability. Proponents may compare it to other architectural patterns or to existing API management approaches, while critics note that, because it is informal, the term offers little concrete guidance without a concrete definition.

Because of its informal status, capii tends to appear only in niche forums, blog posts, or speculative design documents, and it should be interpreted from its surrounding text. It is distinct from formal standards like REST or GraphQL specifications, or from established distributed-systems concepts such as the CAP theorem. See also API design principles, API gateway patterns, and interface standardization while navigating discussions that invoke capii.