Modern IT companies embrace an API (Application programming interface) as an important part of their businesses. Follow the trend and change how you perceive APIs. Build an API before anything else, except business plan (hopefully). Acknowledge the fact that your service will be customer-facing, even if for now the only customer is a web front-end your colleague is working on.
There are a lot of good API design tools. Here are some useful comparisons: 1, 2. My weapon of choice is Swagger, mainly because of prior positive experience and a strong community. After all, who would want to see search results below?
In this post, we dive into designing and implementing an API using Swagger, Spring Boot. We also consider API cooperation, maintenance and documentation.
Read the article here - https://www.easyitblog.info/2017/01/08/api-first-approach-with-swagger/