> ... schemas aren’t free. You have to coördinate between sender and receiver, and you have to worry what happens when someone wants to add a new field to a mes

> ... schemas aren’t free. You have to coördinate between sender and receiver, and you have to worry what happens when someone wants to add a new field to a message type — but in raw JSON, you don’t have to worry, you just toss in the new field and things don’t break. Flexibility is a good thing. Much like type systems in general, you always have a schema, and you always have to worry about what happens when someone adds a field. You just get to choose whether it's explicit and you have to type it alllll the way out allllll the time, or whether it's implicit, and is defined as "whatever all the usages are everywhere". Just as gradual typing is taking over the world (TypeScript, MyPy, etc.), I predict success for something that lets you gradually add schemas to JSON.