Comment by crdoconnor

The JSON spec has no opinion on that and that's a good thing. It is up to you, your language and your parser to decide how large the largest JSON number should be.

Would it be simpler to enforce a global 32 bit or 64 bit limit on those numbers in the spec? I don't think so. Why should the limitations of embedded microcontrollers exchanging data apply to those of astronomical systems and vice versa?