# Facade Pattern

> A design pattern that gives a subsystem one simple entry point, so callers do not depend on its parts.

Record: `architecture:facade-pattern`
Kind: pattern
Layer: [Design Patterns Core](https://banes-lab.com/records/layer/design-patterns-core.md)
Severity: recommended
Scope: module, subsystem, API
Canonical: https://banes-lab.com/ontology#architecture-facade-pattern

Listed in [Architecture principles](https://banes-lab.com/api/records/architecture.md), after [Adapter Pattern](https://banes-lab.com/records/architecture/adapter-pattern.md) and before [Proxy Pattern](https://banes-lab.com/records/architecture/proxy-pattern.md).

## Repair

- Refactored by: Introduce Facade
- Detected by: broad dependency surface to subsystem
- Violated by: consumers depending on many subsystem internals
- Measured by: consumer dependency count
- Enforced by: API boundary rules

## Requires

- [Subsystem Complexity](https://banes-lab.com/records/lexicon/subsystem-complexity.md)

## Reinforces

- [Encapsulation](https://banes-lab.com/records/architecture/encapsulation.md)
- [Information Hiding](https://banes-lab.com/records/architecture/information-hiding.md)

## Enables

- [Simplified Access](https://banes-lab.com/records/lexicon/simplified-access.md)

## Conflicts with

- [Leaky Subsystem API](https://banes-lab.com/records/lexicon/leaky-subsystem-api.md)

## In tension with

- [Over-Centralization](https://banes-lab.com/records/lexicon/over-centralization.md)

## Tensions

- [Facade Pattern / Over-Centralization](https://banes-lab.com/records/tension/facade-pattern-over-centralization.md)

## Severity

- [recommended](https://banes-lab.com/records/vocabulary/severity-recommended.md)

## Category

- [Structural Patterns](https://banes-lab.com/records/architecture-category/structural-patterns.md)

## Linked from

- [Core Modular Design](https://banes-lab.com/ontology/principles/architecture-category-core-modular-design.md)
- [Structural Patterns](https://banes-lab.com/ontology/lexicon/lexicon-category-structural-patterns.md)
- [Severity levels](https://banes-lab.com/ontology/schema/the-vocabulary-severity.md)
- [The resolutions](https://banes-lab.com/ontology/schema/the-resolutions.md)