# Summary * [Introduction](README.md) * [Core Principles](core-principles/README.md) * [API First](core-principles/api-first.md) * [OpenAPI Specification](core-principles/openapi-specification.md) * [Apiary](core-principles/apiary.md) * [Version Control System](core-principles/version-control-system.md) * [Contract](core-principles/contract.md) * [Testing](core-principles/testing.md) * [Design Maturity](core-principles/design-maturity.md) * [Implementation Maturity](core-principles/implementation-maturity.md) * [Robustness](core-principles/robustness.md) * [Minimal API Surface](core-principles/minimal-api-surface.md)