So much this. People (and languages) seem to forget that an HTTP request is a string of bytes (another “bottom of the stack”). A JSON object isn’t a type, it’s a string of bytes.
I would say it's more accurate to call an HTTP request or a JSON object a subset of the set of all strings.
If step out the realm of sets and into programing languages types are very similar to sets. Heck there is type theory which also is very similar to set theory, but has a few difference.
