imagine Earth was a JSON file. Now imagine you never have to argue with flat earthers online ever again. Json:api is a set of specifications which define how JSON files should be formatted. More specifically, json:api defines shared conventions for building APIs, like how JSON responses should look like. No more arguing if it's round or flat, an array or a string. Json:api standardizes how a client should request that resources be fetched or modified, and how a server should respond to those requests. This also helps keep the number of requests and the amount of data transmitted between clients and servers to a minimum.
“How come you never fight with your wife?” “We use the json:api specification for everything.”