Stable Interfaces

Kind: quality-attribute

Layer: Contracts Core

Record: architecture:stable-interfaces

Severity: mandatory

Scope: API, module, service

Canonical: Ontology

The degree to which a public interface keeps its signatures and meaning across releases.

Listed in Architecture principles, after Explicit Contracts and before Interface-Based Design.

Requires

• Versioning
• Backward Compatibility

Reinforces

• Low Coupling
• Replaceability

Enables

• Independent Consumers

Conflicts with

• Breaking Change

In tension with

• Evolution Speed

Tensions

• Stable Interfaces / Evolution Speed

Violated by

• Unversioned Breaking Change
• Schema Drift

Refactored by

• Versioning
• Extract Adapter
• Gradual Deprecation

Severity

• mandatory

Category

• Contracts / Interfaces / Compatibility

Required by

• Explicit Boundaries
• Runtime Extensibility
• Explicit Contracts
• Interface-Based Design
• API Contract
• Encapsulation
• Composability
• Dependency Inversion Principle
• Plugin Architecture
• Extension Points

Reinforced by

• Principle of Least Surprise

Linked from

• Domain Architecture
• Runtime Discovery / Dynamic Binding
• Contracts / Interfaces / Compatibility
• Core Modular Design
• SOLID / Object-Oriented Design
• Plugin / Extensibility / IoC
• Schema / Canonical Data / Semantics
• Codebase / System Architecture Styles
• Contracts / Interfaces / Compatibility
• Severity levels
• The resolutions