Honestly, the only thing that surprises me is you're being pedantic, and encoding int64s as strings. I know you know JSON is nominally only 53-bit safe, becaus

Honestly, the only thing that surprises me is you're being pedantic, and encoding int64s as strings. I know you know JSON is nominally only 53-bit safe, because JS numbers are doubles. But in practice I'd wager most JSON libraries can handle 64-bit integers.