Implement JSON API or add HAL documents or change to HAPI

[nuest]

HAL standardizes links between API responses, see http://stateless.co/hal_specification.html

[nuest]

Goes into the same direction: follow http://jsonapi.org/format/

[nuest]

Completely different approach for "human readable" APIs: https://github.com/jheising/HAPI