Here is what works, from my experience: Any development which involves multiple teams (or multiple developers for tjhat matter) must start with definition of t

Here is what works, from my experience: Any development which involves multiple teams (or multiple developers for tjhat matter) must start with definition of the API. Write a Word document, assign a version, distribute to all involved. Then, create mock calls and mock data according to the specification (this answers your question). FE devs can work in parallel while the back end implement. Any modifications to the interface result in a new revision of the API spec. Repeat. Swagger is not an API spec, as it does not allow to see what changed from 2.1 to 3.3, for example. Use Word, discuss the changes before committing to modification of the API.