i’ve used this same technique for a few years now. I use it primarily to develop UI features in parallel with backend development. The mock api’s are great for exploring the layout edge cases (how does it react to small and large data returns). Saves a lot of iterations when i do final integration with the real api. json-server works great for simple api’s but i’ve used node & express in the past to provide more dynamic api’s, including simulating file uploads. Regardless of which approach you take, this is a great technique to have in your toolbox.