# 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)
  * [Rules for Extending](core-principles/rules-for-extending.md)
* [Protocol](protocol/README.md)
  * [HTTP](protocol/http.md)
  * [TLS](protocol/tls.md)
  * [Know your HTTP](protocol/know-your-http.md)
  * [Separate Concerns](protocol/separate-concerns.md)
  * [Content Negotiation](protocol/content-negotiation.md)
  * [Request Methods](protocol/use-appropriate-methods.md)
  * [Status Codes](protocol/use-appropriate-status-codes.md)
  * [Caching](protocol/caching.md)
* [Message](message/README.md)
  * [Message Formats](message/message-formats.md)
  * [Siren](message/siren.md)
  * [Error Reporting](message/error-reporting.md)
* [Evolution](evolution/README.md)
  * [Changes and Versioning](evolution/versioning.md)
* JSON
* [API Clients](clients/README.md)
  * [Loose Coupling](clients/loose-coupling.md)
* [Miscellaneous](miscellaneous.md)
* [Acknowledgements](acknowledgements.md)