# Subject/Subscriber Contract

> The requirement of an agreed interface by which subjects notify and subscribers receive updates.

Record: `lex:subject-subscriber-contract`
Kind: constraint
Layer: [Design Patterns Core](https://banes-lab.com/records/layer/design-patterns-core.md)
Canonical: https://banes-lab.com/ontology/lexicon#lex-subject-subscriber-contract

## category

- [Behavioral Patterns](https://banes-lab.com/records/lex-category/behavioral-patterns.md)

## referenced-by

- [Observer Pattern](https://banes-lab.com/records/arch/observer-pattern.md)