observer pattern
compound.compound. a way of designing software where one object keeps a list of other objects and tells them automatically when its state changes. You use this so that different parts of a program stay updated without being tightly connected to each other.
compound. a software design pattern in which an object, called the subject, maintains a list of its dependents, called observers, and notifies them automatically of any state changes. This pattern facilitates loose coupling by allowing the subject to interact with observers through a generic interface rather than specific implementations.
The app uses the observer pattern to update the screen when data changes.
By implementing the observer pattern, the developers ensured that the user interface and the database remained synchronized without direct dependencies.
The observer pattern is fundamental to event-driven architectures, enabling a one-to-many dependency relationship where multiple subscriber objects can react dynamically to events published by a single provider.
A compound of the English noun observer and the noun pattern. The term was formalised in the 1994 book Design Patterns, authored by Erich Gamma, Richard Helm, Ralph Johnson, and John Vlissides.
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.
Commonly used in the context of object-oriented programming and software architecture.
Last updated July 22, 2026