Stub

A stub is a brief, incomplete item that is intended to be expanded later. In encyclopedias and wikis, a stub article contains only a small amount of information and is not sufficient to cover a topic in depth. Stub articles are labeled with a stub marker and placed into stub categories so contributors know they should be expanded. Notability guidelines typically apply to determine whether a topic may be eligible for expansion into a full article.

In computing and software development, a stub is a minimal implementation used as a placeholder for a module, function, or component that is not yet implemented or is difficult to integrate. Stub code can return fixed values, perform simple logging, or simulate behavior to enable testing, compilation, or integration of larger systems. A stub may be a test stub, API stub, or a remote procedure call stub. In RPC and distributed systems, a client-side stub acts as a proxy for a remote object, while a server-side skeleton handles requests; stubs are often generated from interface definitions and replaced by real implementations later.

Stubs serve as scaffolding to accelerate development, facilitate unit testing, and allow parts of a system to be developed in parallel. They differ from mocks or fakes in that stubs provide predefined responses without asserting behavior, whereas mocks are designed to verify interactions. The term also appears in other contexts, where any temporary or minimal implementation stands in for a more complete component during the development lifecycle.