When I build a new web app, I start with a REST API. The input and output are known, so bugs are less likely. As I roll out new API methods, I add it to a postm

When I build a new web app, I start with a REST API. The input and output are known, so bugs are less likely. As I roll out new API methods, I add it to a postman collection, and add a couple of tests to it. Then with each deploy, I point my postman to that environment and hit run. When building the client application, I typically just manually test as I go along. Bugs happen, but because the foundation code is all REST API, the bugs are usually and easily fixed.