Code-First vs. Design-First
APIs are a product and should be treated as such. In an API design-first development process, API architects begin with writing a specification and engaging all stakeholders in the process from its inception.
The result of a design-first process is an API product that is comprehensive, consistent, and understandable by both collaborators and machines.
Treating your APIs as products means using a design-first approach to produce the best possible product.