This Kong Summit 2020 session focuses on the war stories, and subsequently the patterns HyperCurrent employed, from building an API chargeback/monetization product using OAS, Kotlin, Spring Boot and Kong. We will discuss how a programmatic approach can be used to deliver an elegant REST-ful API while enforcing an anti-corruption layer for domain logic without writing API contracts by hand. By using Kotlin and Spring Boot along with a controller/DTO approach, we can automatically produce an OAS contract, HTML docs, a console and a client side SDK.